19974964644 has 18 divisors (see below), whose sum is σ = 50492271830. Its totient is φ = 6658321536.

The previous prime is 19974964631. The next prime is 19974964649. The reversal of 19974964644 is 44646947991.

19974964644 is a `hidden beast` number, since 19 + 9 + 74 + 96 + 464 + 4 = 666.

It can be written as a sum of positive squares in only one way, i.e., 13071348900 + 6903615744 = 114330^2 + 83088^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is not an unprimeable number, because it can be changed into a prime (19974964649) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 277430029 + ... + 277430100.

Almost surely, 2^19974964644 is an apocalyptic number.

It is an amenable number.

19974964644 is an abundant number, since it is smaller than the sum of its proper divisors (30517307186).

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

19974964644 is a wasteful number, since it uses less digits than its factorization.

19974964644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 554860139 (or 554860134 counting only the distinct ones).

The product of its digits is 47029248, while the sum is 63.

The spelling of 19974964644 in words is "nineteen billion, nine hundred seventy-four million, nine hundred sixty-four thousand, six hundred forty-four".