21023255400 has 384 divisors, whose sum is σ = 76109414400. Its totient is φ = 4701542400.

The previous prime is 21023255387. The next prime is 21023255423. The reversal of 21023255400 is 455232012.

It is a super-2 number, since 2×21023255400² (a number of 21 digits) contains 22 as substring.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 58560421 + ... + 58560779.

It is an arithmetic number, because the mean of its divisors is an integer number (198201600).

Almost surely, 2^21023255400 is an apocalyptic number.

21023255400 is a gapful number since it is divisible by the number (20) 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 21023255400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38054707200).

21023255400 is an abundant number, since it is smaller than the sum of its proper divisors (55086159000).

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

21023255400 is a wasteful number, since it uses less digits than its factorization.

21023255400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 649 (or 640 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 24.

Adding to 21023255400 its reverse (455232012), we get a palindrome (21478487412).

The spelling of 21023255400 in words is "twenty-one billion, twenty-three million, two hundred fifty-five thousand, four hundred".