1645546631 has 4 divisors (see below), whose sum is σ = 1645714032. Its totient is φ = 1645379232.

The previous prime is 1645546627. The next prime is 1645546649. The reversal of 1645546631 is 1366455461.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1645546631 - 2² = 1645546627 is a prime.

It is a super-2 number, since 2×1645546631² = 5415647429590900322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1645546601) 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, 67970 + ... + 88943.

It is an arithmetic number, because the mean of its divisors is an integer number (411428508).

Almost surely, 2^1645546631 is an apocalyptic number.

1645546631 is a deficient number, since it is larger than the sum of its proper divisors (167401).

1645546631 is a wasteful number, since it uses less digits than its factorization.

1645546631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 167400.

The product of its digits is 259200, while the sum is 41.

The square root of 1645546631 is about 40565.3378021187. The cubic root of 1645546631 is about 1180.6016827597.

The spelling of 1645546631 in words is "one billion, six hundred forty-five million, five hundred forty-six thousand, six hundred thirty-one".