19890874647 has 64 divisors (see below), whose sum is σ = 33990528000. Its totient is φ = 11261047680.

The previous prime is 19890874643. The next prime is 19890874673. The reversal of 19890874647 is 74647809891.

19890874647 is a `hidden beast` number, since 1 + 9 + 8 + 90 + 87 + 464 + 7 = 666.

It is not a de Polignac number, because 19890874647 - 2² = 19890874643 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19890874643) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 16079313 + ... + 16080549.

It is an arithmetic number, because the mean of its divisors is an integer number (531102000).

Almost surely, 2^19890874647 is an apocalyptic number.

19890874647 is a deficient number, since it is larger than the sum of its proper divisors (14099653353).

19890874647 is a wasteful number, since it uses less digits than its factorization.

19890874647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1973 (or 1967 counting only the distinct ones).

The product of its (nonzero) digits is 24385536, while the sum is 63.

The spelling of 19890874647 in words is "nineteen billion, eight hundred ninety million, eight hundred seventy-four thousand, six hundred forty-seven".