31720431 has 8 divisors (see below), whose sum is σ = 42528304. Its totient is φ = 21029760.

The previous prime is 31720421. The next prime is 31720439. The reversal of 31720431 is 13402713.

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

It is not a de Polignac number, because 31720431 - 2¹¹ = 31718383 is a prime.

It is a super-2 number, since 2×31720431² = 2012371485651522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31720398 and 31720407.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31720439) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28666 + ... + 29751.

It is an arithmetic number, because the mean of its divisors is an integer number (5316038).

Almost surely, 2^31720431 is an apocalyptic number.

31720431 is a deficient number, since it is larger than the sum of its proper divisors (10807873).

31720431 is a wasteful number, since it uses less digits than its factorization.

31720431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58601.

The product of its (nonzero) digits is 504, while the sum is 21.

The square root of 31720431 is about 5632.0893991484. The cubic root of 31720431 is about 316.5529461773.

The spelling of 31720431 in words is "thirty-one million, seven hundred twenty thousand, four hundred thirty-one".