21319597940 has 12 divisors (see below), whose sum is σ = 44771155716. Its totient is φ = 8527839168.

The previous prime is 21319597939. The next prime is 21319597961. The reversal of 21319597940 is 4979591312.

It can be written as a sum of positive squares in 2 ways, for example, as 12898599184 + 8420998756 = 113572^2 + 91766^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 532989929 + ... + 532989968.

It is an arithmetic number, because the mean of its divisors is an integer number (3730929643).

Almost surely, 2^21319597940 is an apocalyptic number.

21319597940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21319597940 is an abundant number, since it is smaller than the sum of its proper divisors (23451557776).

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

21319597940 is a wasteful number, since it uses less digits than its factorization.

21319597940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1065979906 (or 1065979904 counting only the distinct ones).

The product of its (nonzero) digits is 612360, while the sum is 50.

The spelling of 21319597940 in words is "twenty-one billion, three hundred nineteen million, five hundred ninety-seven thousand, nine hundred forty".