21003869952 has 216 divisors, whose sum is σ = 67324519808. Its totient is φ = 6253977600.

The previous prime is 21003869917. The next prime is 21003870077. The reversal of 21003869952 is 25996830012.

21003869952 is a `hidden beast` number, since 210 + 0 + 386 + 9 + 9 + 52 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 21003869898 and 21003869907.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 917202 + ... + 939822.

Almost surely, 2^21003869952 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 21003869952, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33662259904).

21003869952 is an abundant number, since it is smaller than the sum of its proper divisors (46320649856).

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

21003869952 is a wasteful number, since it uses less digits than its factorization.

21003869952 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22687 (or 22670 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 45.

The spelling of 21003869952 in words is "twenty-one billion, three million, eight hundred sixty-nine thousand, nine hundred fifty-two".