21161020264 has 32 divisors (see below), whose sum is σ = 40201056000. Its totient is φ = 10440885312.

The previous prime is 21161020261. The next prime is 21161020273. The reversal of 21161020264 is 46202016112.

It is a happy number.

It is a super-2 number, since 2×21161020264² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21161020261) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1299517 + ... + 1315699.

It is an arithmetic number, because the mean of its divisors is an integer number (1256283000).

Almost surely, 2^21161020264 is an apocalyptic number.

It is an amenable number.

21161020264 is a deficient number, since it is larger than the sum of its proper divisors (19040035736).

21161020264 is a wasteful number, since it uses less digits than its factorization.

21161020264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18337 (or 18333 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 25.

Adding to 21161020264 its reverse (46202016112), we get a palindrome (67363036376).

The spelling of 21161020264 in words is "twenty-one billion, one hundred sixty-one million, twenty thousand, two hundred sixty-four".