1631645973 has 6 divisors (see below), whose sum is σ = 2356821974. Its totient is φ = 1087763976.

The previous prime is 1631645929. The next prime is 1631645993. The reversal of 1631645973 is 3795461361.

It is a happy number.

1631645973 is a `hidden beast` number, since 1 + 631 + 6 + 4 + 5 + 9 + 7 + 3 = 666.

It can be written as a sum of positive squares in only one way, i.e., 852231249 + 779414724 = 29193^2 + 27918^2 .

It is not a de Polignac number, because 1631645973 - 2²⁴ = 1614868757 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1631645903) 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, 90646990 + ... + 90647007.

Almost surely, 2^1631645973 is an apocalyptic number.

It is an amenable number.

1631645973 is a deficient number, since it is larger than the sum of its proper divisors (725176001).

1631645973 is a wasteful number, since it uses less digits than its factorization.

1631645973 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 181294003 (or 181294000 counting only the distinct ones).

The product of its digits is 408240, while the sum is 45.

The square root of 1631645973 is about 40393.6377787394. The cubic root of 1631645973 is about 1177.2679234836.

The spelling of 1631645973 in words is "one billion, six hundred thirty-one million, six hundred forty-five thousand, nine hundred seventy-three".