21507233758 has 4 divisors (see below), whose sum is σ = 32260850640. Its totient is φ = 10753616878.

The previous prime is 21507233743. The next prime is 21507233771. The reversal of 21507233758 is 85733270512.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a super-2 number, since 2×21507233758² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5376808438 + ... + 5376808441.

It is an arithmetic number, because the mean of its divisors is an integer number (8065212660).

Almost surely, 2^21507233758 is an apocalyptic number.

21507233758 is a deficient number, since it is larger than the sum of its proper divisors (10753616882).

21507233758 is a wasteful number, since it uses less digits than its factorization.

21507233758 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10753616881.

The product of its (nonzero) digits is 352800, while the sum is 43.

The spelling of 21507233758 in words is "twenty-one billion, five hundred seven million, two hundred thirty-three thousand, seven hundred fifty-eight".