1645326131 has 4 divisors (see below), whose sum is σ = 1645721064. Its totient is φ = 1644931200.

The previous prime is 1645326121. The next prime is 1645326149. The reversal of 1645326131 is 1316235461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1316235461 = 43 ⋅30610127.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1645326131 is a prime.

It is a super-2 number, since 2×1645326131² = 5414196154702858322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1645326121) 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, 191150 + ... + 199571.

It is an arithmetic number, because the mean of its divisors is an integer number (411430266).

Almost surely, 2^1645326131 is an apocalyptic number.

1645326131 is a deficient number, since it is larger than the sum of its proper divisors (394933).

1645326131 is an equidigital number, since it uses as much as digits as its factorization.

1645326131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 394932.

The product of its digits is 12960, while the sum is 32.

The square root of 1645326131 is about 40562.6198734746. The cubic root of 1645326131 is about 1180.5489476392.

The spelling of 1645326131 in words is "one billion, six hundred forty-five million, three hundred twenty-six thousand, one hundred thirty-one".