31720749 has 16 divisors (see below), whose sum is σ = 44323200. Its totient is φ = 20140736.

The previous prime is 31720699. The next prime is 31720771. The reversal of 31720749 is 94702713.

It is a cyclic number.

It is not a de Polignac number, because 31720749 - 2⁹ = 31720237 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31720049) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17707 + ... + 19415.

It is an arithmetic number, because the mean of its divisors is an integer number (2770200).

Almost surely, 2^31720749 is an apocalyptic number.

It is an amenable number.

31720749 is a deficient number, since it is larger than the sum of its proper divisors (12602451).

31720749 is a wasteful number, since it uses less digits than its factorization.

31720749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2004.

The product of its (nonzero) digits is 10584, while the sum is 33.

The square root of 31720749 is about 5632.1176301636. The cubic root of 31720749 is about 316.5540039971.

The spelling of 31720749 in words is "thirty-one million, seven hundred twenty thousand, seven hundred forty-nine".