19712906981 has 4 divisors (see below), whose sum is σ = 19766620992. Its totient is φ = 19659192972.

The previous prime is 19712906929. The next prime is 19712907013. The reversal of 19712906981 is 18960921791.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 19712906981 - 2²² = 19708712677 is a prime.

It is a super-2 number, since 2×19712906981² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19712906911) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26856455 + ... + 26857188.

It is an arithmetic number, because the mean of its divisors is an integer number (4941655248).

Almost surely, 2^19712906981 is an apocalyptic number.

It is an amenable number.

19712906981 is a deficient number, since it is larger than the sum of its proper divisors (53714011).

19712906981 is an equidigital number, since it uses as much as digits as its factorization.

19712906981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53714010.

The product of its (nonzero) digits is 489888, while the sum is 53.

The spelling of 19712906981 in words is "nineteen billion, seven hundred twelve million, nine hundred six thousand, nine hundred eighty-one".