19487972657 has 4 divisors (see below), whose sum is σ = 20335275840. Its totient is φ = 18640669476.

The previous prime is 19487972599. The next prime is 19487972663. The reversal of 19487972657 is 75627978491.

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 19487972657 - 2²⁴ = 19471195441 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 19487972593 and 19487972602.

It is not an unprimeable number, because it can be changed into a prime (19487972857) 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, 423651557 + ... + 423651602.

It is an arithmetic number, because the mean of its divisors is an integer number (5083818960).

Almost surely, 2^19487972657 is an apocalyptic number.

It is an amenable number.

19487972657 is a deficient number, since it is larger than the sum of its proper divisors (847303183).

19487972657 is an equidigital number, since it uses as much as digits as its factorization.

19487972657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 847303182.

The product of its digits is 53343360, while the sum is 65.

The spelling of 19487972657 in words is "nineteen billion, four hundred eighty-seven million, nine hundred seventy-two thousand, six hundred fifty-seven".