31321999 has 8 divisors (see below), whose sum is σ = 31821120. Its totient is φ = 30825600.

The previous prime is 31321987. The next prime is 31322023. The reversal of 31321999 is 99912313.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 31321999 - 2⁵ = 31321967 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31321919) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40779 + ... + 41539.

It is an arithmetic number, because the mean of its divisors is an integer number (3977640).

Almost surely, 2^31321999 is an apocalyptic number.

31321999 is a deficient number, since it is larger than the sum of its proper divisors (499121).

31321999 is an equidigital number, since it uses as much as digits as its factorization.

31321999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1361.

The product of its digits is 13122, while the sum is 37.

The square root of 31321999 is about 5596.6060250834. The cubic root of 31321999 is about 315.2219784152.

The spelling of 31321999 in words is "thirty-one million, three hundred twenty-one thousand, nine hundred ninety-nine".