21264204550 has 12 divisors (see below), whose sum is σ = 39551420556. Its totient is φ = 8505681800.

The previous prime is 21264204539. The next prime is 21264204551. The reversal of 21264204550 is 5540246212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21264204551) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 212641996 + ... + 212642095.

It is an arithmetic number, because the mean of its divisors is an integer number (3295951713).

Almost surely, 2^21264204550 is an apocalyptic number.

21264204550 is a deficient number, since it is larger than the sum of its proper divisors (18287216006).

21264204550 is a wasteful number, since it uses less digits than its factorization.

21264204550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 425284103 (or 425284098 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 31.

The spelling of 21264204550 in words is "twenty-one billion, two hundred sixty-four million, two hundred four thousand, five hundred fifty".