1645731187 has 2 divisors, whose sum is σ = 1645731188. Its totient is φ = 1645731186.

The previous prime is 1645731169. The next prime is 1645731203. The reversal of 1645731187 is 7811375461.

It is a strong prime.

It is an emirp because it is prime and its reverse (7811375461) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1645731187 is a prime.

It is a super-2 number, since 2×1645731187² = 5416862279728857938, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1645731107) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 822865593 + 822865594.

It is an arithmetic number, because the mean of its divisors is an integer number (822865594).

Almost surely, 2^1645731187 is an apocalyptic number.

1645731187 is a deficient number, since it is larger than the sum of its proper divisors (1).

1645731187 is an equidigital number, since it uses as much as digits as its factorization.

1645731187 is an evil number, because the sum of its binary digits is even.

The product of its digits is 141120, while the sum is 43.

The square root of 1645731187 is about 40567.6125375896. The cubic root of 1645731187 is about 1180.6458178361.

The spelling of 1645731187 in words is "one billion, six hundred forty-five million, seven hundred thirty-one thousand, one hundred eighty-seven".