21021525011 has 4 divisors (see below), whose sum is σ = 21229659024. Its totient is φ = 20813391000.

The previous prime is 21021524957. The next prime is 21021525023. The reversal of 21021525011 is 11052512012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21021525011 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21021525071) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 104066855 + ... + 104067056.

It is an arithmetic number, because the mean of its divisors is an integer number (5307414756).

Almost surely, 2^21021525011 is an apocalyptic number.

21021525011 is a deficient number, since it is larger than the sum of its proper divisors (208134013).

21021525011 is a wasteful number, since it uses less digits than its factorization.

21021525011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 208134012.

The product of its (nonzero) digits is 200, while the sum is 20.

The spelling of 21021525011 in words is "twenty-one billion, twenty-one million, five hundred twenty-five thousand, eleven".