19965173940 has 72 divisors (see below), whose sum is σ = 60583148808. Its totient is φ = 5322101760.

The previous prime is 19965173929. The next prime is 19965173971. The reversal of 19965173940 is 4937156991.

19965173940 is a `hidden beast` number, since 1 + 9 + 96 + 517 + 39 + 4 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 1214801316 + 18750372624 = 34854^2 + 136932^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 512760 + ... + 550320.

Almost surely, 2^19965173940 is an apocalyptic number.

19965173940 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19965173940 is an abundant number, since it is smaller than the sum of its proper divisors (40617974868).

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

19965173940 is a wasteful number, since it uses less digits than its factorization.

19965173940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40529 (or 40524 counting only the distinct ones).

The product of its (nonzero) digits is 1837080, while the sum is 54.

The spelling of 19965173940 in words is "nineteen billion, nine hundred sixty-five million, one hundred seventy-three thousand, nine hundred forty".