21018572 has 12 divisors (see below), whose sum is σ = 37638216. Its totient is φ = 10264800.

The previous prime is 21018563. The next prime is 21018601. The reversal of 21018572 is 27581012.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 60929 + ... + 61272.

It is an arithmetic number, because the mean of its divisors is an integer number (3136518).

Almost surely, 2^21018572 is an apocalyptic number.

It is an amenable number.

21018572 is a deficient number, since it is larger than the sum of its proper divisors (16619644).

21018572 is a wasteful number, since it uses less digits than its factorization.

21018572 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122248 (or 122246 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 26.

The square root of 21018572 is about 4584.6016184615. The cubic root of 21018572 is about 275.9737250069.

Adding to 21018572 its reverse (27581012), we get a palindrome (48599584).

The spelling of 21018572 in words is "twenty-one million, eighteen thousand, five hundred seventy-two".