21252653604 has 288 divisors, whose sum is σ = 69838030080. Its totient is φ = 5291910144.

The previous prime is 21252653603. The next prime is 21252653621. The reversal of 21252653604 is 40635625212.

21252653604 is a `hidden beast` number, since 2 + 1 + 25 + 26 + 5 + 3 + 604 = 666.

It is a super-2 number, since 2×21252653604² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (21252653603) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 34669602 + ... + 34670214.

It is an arithmetic number, because the mean of its divisors is an integer number (242493160).

Almost surely, 2^21252653604 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21252653604, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34919015040).

21252653604 is an abundant number, since it is smaller than the sum of its proper divisors (48585376476).

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

21252653604 is a wasteful number, since it uses less digits than its factorization.

21252653604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1219 (or 1214 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 36.

The spelling of 21252653604 in words is "twenty-one billion, two hundred fifty-two million, six hundred fifty-three thousand, six hundred four".