21731757642 has 192 divisors, whose sum is σ = 58767072000. Its totient is φ = 5783944320.

The previous prime is 21731757631. The next prime is 21731757767. The reversal of 21731757642 is 24675713712.

21731757642 is a `hidden beast` number, since 2 + 1 + 7 + 31 + 7 + 576 + 42 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 7154148 + ... + 7157184.

It is an arithmetic number, because the mean of its divisors is an integer number (306078500).

Almost surely, 2^21731757642 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21731757642, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29383536000).

21731757642 is an abundant number, since it is smaller than the sum of its proper divisors (37035314358).

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

21731757642 is a wasteful number, since it uses less digits than its factorization.

21731757642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3146 (or 3129 counting only the distinct ones).

The product of its digits is 493920, while the sum is 45.

The spelling of 21731757642 in words is "twenty-one billion, seven hundred thirty-one million, seven hundred fifty-seven thousand, six hundred forty-two".