21511532065 has 16 divisors (see below), whose sum is σ = 25936739136. Its totient is φ = 17127400000.

The previous prime is 21511532057. The next prime is 21511532071. The reversal of 21511532065 is 56023511512.

It is not a de Polignac number, because 21511532065 - 2³ = 21511532057 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1815099 + ... + 1826911.

It is an arithmetic number, because the mean of its divisors is an integer number (1621046196).

Almost surely, 2^21511532065 is an apocalyptic number.

It is an amenable number.

21511532065 is a deficient number, since it is larger than the sum of its proper divisors (4425207071).

21511532065 is a wasteful number, since it uses less digits than its factorization.

21511532065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13520.

The product of its (nonzero) digits is 9000, while the sum is 31.

The spelling of 21511532065 in words is "twenty-one billion, five hundred eleven million, five hundred thirty-two thousand, sixty-five".