21520145264 has 10 divisors (see below), whose sum is σ = 41695281480. Its totient is φ = 10760072624.

The previous prime is 21520145261. The next prime is 21520145279. The reversal of 21520145264 is 46254102512.

It is a self number, because there is not a number n which added to its sum of digits gives 21520145264.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21520145261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 672504524 + ... + 672504555.

It is an arithmetic number, because the mean of its divisors is an integer number (4169528148).

Almost surely, 2^21520145264 is an apocalyptic number.

It is an amenable number.

21520145264 is a deficient number, since it is larger than the sum of its proper divisors (20175136216).

21520145264 is a wasteful number, since it uses less digits than its factorization.

21520145264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1345009087 (or 1345009081 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 32.

Adding to 21520145264 its reverse (46254102512), we get a palindrome (67774247776).

The spelling of 21520145264 in words is "twenty-one billion, five hundred twenty million, one hundred forty-five thousand, two hundred sixty-four".