21551317432 has 8 divisors (see below), whose sum is σ = 40408720200. Its totient is φ = 10775658712.

The previous prime is 21551317387. The next prime is 21551317457. The reversal of 21551317432 is 23471315512.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1346957332 + ... + 1346957347.

It is an arithmetic number, because the mean of its divisors is an integer number (5051090025).

Almost surely, 2^21551317432 is an apocalyptic number.

It is an amenable number.

21551317432 is a deficient number, since it is larger than the sum of its proper divisors (18857402768).

21551317432 is a wasteful number, since it uses less digits than its factorization.

21551317432 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2693914685 (or 2693914681 counting only the distinct ones).

The product of its digits is 25200, while the sum is 34.

The spelling of 21551317432 in words is "twenty-one billion, five hundred fifty-one million, three hundred seventeen thousand, four hundred thirty-two".