21004023552 has 72 divisors (see below), whose sum is σ = 57201454464. Its totient is φ = 6838508544.

The previous prime is 21004023503. The next prime is 21004023553. The reversal of 21004023552 is 25532040012.

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 (21004023553) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 284988 + ... + 351035.

Almost surely, 2^21004023552 is an apocalyptic number.

It is an amenable number.

21004023552 is an abundant number, since it is smaller than the sum of its proper divisors (36197430912).

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

21004023552 is an equidigital number, since it uses as much as digits as its factorization.

21004023552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 636085 (or 636071 counting only the distinct ones).

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

Adding to 21004023552 its reverse (25532040012), we get a palindrome (46536063564).

The spelling of 21004023552 in words is "twenty-one billion, four million, twenty-three thousand, five hundred fifty-two".