21791953500 has 48 divisors (see below), whose sum is σ = 63458172960. Its totient is φ = 5811187200.

The previous prime is 21791953439. The next prime is 21791953507. The reversal of 21791953500 is 535919712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21791953507) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 7262485 + ... + 7265484.

It is an arithmetic number, because the mean of its divisors is an integer number (1322045270).

Almost surely, 2^21791953500 is an apocalyptic number.

21791953500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21791953500 is an abundant number, since it is smaller than the sum of its proper divisors (41666219460).

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

21791953500 is a wasteful number, since it uses less digits than its factorization.

21791953500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14527991 (or 14527979 counting only the distinct ones).

The product of its (nonzero) digits is 85050, while the sum is 42.

The spelling of 21791953500 in words is "twenty-one billion, seven hundred ninety-one million, nine hundred fifty-three thousand, five hundred".