21164033240 has 32 divisors (see below), whose sum is σ = 54421800480. Its totient is φ = 7256239872.

The previous prime is 21164033207. The next prime is 21164033251. The reversal of 21164033240 is 4233046112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 37792637 + ... + 37793196.

It is an arithmetic number, because the mean of its divisors is an integer number (1700681265).

Almost surely, 2^21164033240 is an apocalyptic number.

21164033240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21164033240 is an abundant number, since it is smaller than the sum of its proper divisors (33257767240).

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

21164033240 is a wasteful number, since it uses less digits than its factorization.

21164033240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75585851 (or 75585847 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 26.

Adding to 21164033240 its reverse (4233046112), we get a palindrome (25397079352).

The spelling of 21164033240 in words is "twenty-one billion, one hundred sixty-four million, thirty-three thousand, two hundred forty".