21001362144 has 192 divisors, whose sum is σ = 63611412480. Its totient is φ = 5942914560.

The previous prime is 21001362139. The next prime is 21001362149. The reversal of 21001362144 is 44126310012.

It is an interprime number because it is at equal distance from previous prime (21001362139) and next prime (21001362149).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001362149) 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, 58499437 + ... + 58499795.

It is an arithmetic number, because the mean of its divisors is an integer number (331309440).

Almost surely, 2^21001362144 is an apocalyptic number.

21001362144 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 21001362144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31805706240).

21001362144 is an abundant number, since it is smaller than the sum of its proper divisors (42610050336).

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

21001362144 is a wasteful number, since it uses less digits than its factorization.

21001362144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 973 (or 965 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 24.

Adding to 21001362144 its reverse (44126310012), we get a palindrome (65127672156).

The spelling of 21001362144 in words is "twenty-one billion, one million, three hundred sixty-two thousand, one hundred forty-four".