21787392951 has 48 divisors (see below), whose sum is σ = 32604892320. Its totient is φ = 14010796800.

The previous prime is 21787392943. The next prime is 21787393007. The reversal of 21787392951 is 15929378712.

It is a happy number.

It is not a de Polignac number, because 21787392951 - 2³ = 21787392943 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21787392911) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 16746001 + ... + 16747301.

It is an arithmetic number, because the mean of its divisors is an integer number (679268590).

Almost surely, 2^21787392951 is an apocalyptic number.

21787392951 is a deficient number, since it is larger than the sum of its proper divisors (10817499369).

21787392951 is a wasteful number, since it uses less digits than its factorization.

21787392951 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1856 (or 1853 counting only the distinct ones).

The product of its digits is 1905120, while the sum is 54.

The spelling of 21787392951 in words is "twenty-one billion, seven hundred eighty-seven million, three hundred ninety-two thousand, nine hundred fifty-one".