21500491748 has 12 divisors (see below), whose sum is σ = 38500880880. Its totient is φ = 10500240072.

The previous prime is 21500491739. The next prime is 21500491769. The reversal of 21500491748 is 84719400512.

It is a super-2 number, since 2×21500491748² (a number of 21 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (41) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 62501258 + ... + 62501601.

It is an arithmetic number, because the mean of its divisors is an integer number (3208406740).

Almost surely, 2^21500491748 is an apocalyptic number.

It is an amenable number.

21500491748 is a deficient number, since it is larger than the sum of its proper divisors (17000389132).

21500491748 is a wasteful number, since it uses less digits than its factorization.

21500491748 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125002906 (or 125002904 counting only the distinct ones).

The product of its (nonzero) digits is 80640, while the sum is 41.

The spelling of 21500491748 in words is "twenty-one billion, five hundred million, four hundred ninety-one thousand, seven hundred forty-eight".