19861972945 has 4 divisors (see below), whose sum is σ = 23834367540. Its totient is φ = 15889578352.

The previous prime is 19861972939. The next prime is 19861972969. The reversal of 19861972945 is 54927916891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 54927916891 = 211 ⋅260321881.

It can be written as a sum of positive squares in 2 ways, for example, as 5828253649 + 14033719296 = 76343^2 + 118464^2 .

It is a cyclic number.

It is not a de Polignac number, because 19861972945 - 2³ = 19861972937 is a prime.

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, 1986197290 + ... + 1986197299.

It is an arithmetic number, because the mean of its divisors is an integer number (5958591885).

Almost surely, 2^19861972945 is an apocalyptic number.

It is an amenable number.

19861972945 is a deficient number, since it is larger than the sum of its proper divisors (3972394595).

19861972945 is an equidigital number, since it uses as much as digits as its factorization.

19861972945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3972394594.

The product of its digits is 9797760, while the sum is 61.

The spelling of 19861972945 in words is "nineteen billion, eight hundred sixty-one million, nine hundred seventy-two thousand, nine hundred forty-five".