1631449721999 has 2 divisors, whose sum is σ = 1631449722000. Its totient is φ = 1631449721998.

The previous prime is 1631449721989. The next prime is 1631449722013. The reversal of 1631449721999 is 9991279441361.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1631449721999 - 2²⁴ = 1631432944783 is a prime.

It is a super-2 number, since 2×1631449721999² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1631449721959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 815724860999 + 815724861000.

It is an arithmetic number, because the mean of its divisors is an integer number (815724861000).

Almost surely, 2^{1631449721999} is an apocalyptic number.

1631449721999 is a deficient number, since it is larger than the sum of its proper divisors (1).

1631449721999 is an equidigital number, since it uses as much as digits as its factorization.

1631449721999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 26453952, while the sum is 65.

The spelling of 1631449721999 in words is "one trillion, six hundred thirty-one billion, four hundred forty-nine million, seven hundred twenty-one thousand, nine hundred ninety-nine".