1644491531 has 2 divisors, whose sum is σ = 1644491532. Its totient is φ = 1644491530.

The previous prime is 1644491489. The next prime is 1644491573. The reversal of 1644491531 is 1351944461.

It is a balanced prime because it is at equal distance from previous prime (1644491489) and next prime (1644491573).

It is a cyclic number.

It is not a de Polignac number, because 1644491531 - 2¹⁸ = 1644229387 is a prime.

It is a super-2 number, since 2×1644491531² = 5408704791061447922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1644491231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 822245765 + 822245766.

It is an arithmetic number, because the mean of its divisors is an integer number (822245766).

Almost surely, 2^1644491531 is an apocalyptic number.

1644491531 is a deficient number, since it is larger than the sum of its proper divisors (1).

1644491531 is an equidigital number, since it uses as much as digits as its factorization.

1644491531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 51840, while the sum is 38.

The square root of 1644491531 is about 40552.3307714859. The cubic root of 1644491531 is about 1180.3493007370.

The spelling of 1644491531 in words is "one billion, six hundred forty-four million, four hundred ninety-one thousand, five hundred thirty-one".