1971572661 has 24 divisors (see below), whose sum is σ = 2920563360. Its totient is φ = 1280948256.

The previous prime is 1971572657. The next prime is 1971572711. The reversal of 1971572661 is 1662751791.

1971572661 is a `hidden beast` number, since 1 + 9 + 71 + 572 + 6 + 6 + 1 = 666.

It is not a de Polignac number, because 1971572661 - 2² = 1971572657 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1971572611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 175275 + ... + 186183.

It is an arithmetic number, because the mean of its divisors is an integer number (121690140).

Almost surely, 2^1971572661 is an apocalyptic number.

It is an amenable number.

1971572661 is a deficient number, since it is larger than the sum of its proper divisors (948990699).

1971572661 is a wasteful number, since it uses less digits than its factorization.

1971572661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11425 (or 11422 counting only the distinct ones).

The product of its digits is 158760, while the sum is 45.

The square root of 1971572661 is about 44402.3947664988. The cubic root of 1971572661 is about 1253.9231750894.

The spelling of 1971572661 in words is "one billion, nine hundred seventy-one million, five hundred seventy-two thousand, six hundred sixty-one".