21147400824 has 128 divisors (see below), whose sum is σ = 62191584000. Its totient is φ = 5922892800.

The previous prime is 21147400819. The next prime is 21147400829. The reversal of 21147400824 is 42800474112.

It is an interprime number because it is at equal distance from previous prime (21147400819) and next prime (21147400829).

It is a super-2 number, since 2×21147400824² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21147400829) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 154242 + ... + 257070.

It is an arithmetic number, because the mean of its divisors is an integer number (485871750).

Almost surely, 2^21147400824 is an apocalyptic number.

21147400824 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21147400824, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31095792000).

21147400824 is an abundant number, since it is smaller than the sum of its proper divisors (41044183176).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21147400824 is a wasteful number, since it uses less digits than its factorization.

21147400824 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102909 (or 102905 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 33.

Adding to 21147400824 its reverse (42800474112), we get a palindrome (63947874936).

The spelling of 21147400824 in words is "twenty-one billion, one hundred forty-seven million, four hundred thousand, eight hundred twenty-four".