21718787952 has 40 divisors (see below), whose sum is σ = 56782865664. Its totient is φ = 7152370624.

The previous prime is 21718787933. The next prime is 21718787977. The reversal of 21718787952 is 25978781712.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21718787892 and 21718787901.

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, 2721768 + ... + 2729735.

Almost surely, 2^21718787952 is an apocalyptic number.

It is an amenable number.

21718787952 is an abundant number, since it is smaller than the sum of its proper divisors (35064077712).

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

21718787952 is a wasteful number, since it uses less digits than its factorization.

21718787952 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5451597 (or 5451591 counting only the distinct ones).

The product of its digits is 3951360, while the sum is 57.

The spelling of 21718787952 in words is "twenty-one billion, seven hundred eighteen million, seven hundred eighty-seven thousand, nine hundred fifty-two".