31749921 has 32 divisors (see below), whose sum is σ = 55500800. Its totient is φ = 17554320.

The previous prime is 31749919. The next prime is 31749923. The reversal of 31749921 is 12994713.

It is an interprime number because it is at equal distance from previous prime (31749919) and next prime (31749923).

It is not a de Polignac number, because 31749921 - 2¹ = 31749919 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 (31749923) 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 in 31 ways as a sum of consecutive naturals, for example, 3150 + ... + 8568.

It is an arithmetic number, because the mean of its divisors is an integer number (1734400).

Almost surely, 2^31749921 is an apocalyptic number.

31749921 is a gapful number since it is divisible by the number (31) formed by its first and last digit.

It is an amenable number.

31749921 is a deficient number, since it is larger than the sum of its proper divisors (23750879).

31749921 is a wasteful number, since it uses less digits than its factorization.

31749921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5466 (or 5460 counting only the distinct ones).

The product of its digits is 13608, while the sum is 36.

The square root of 31749921 is about 5634.7068246715. The cubic root of 31749921 is about 316.6510139385.

The spelling of 31749921 in words is "thirty-one million, seven hundred forty-nine thousand, nine hundred twenty-one".