31640430 has 64 divisors (see below), whose sum is σ = 78236928. Its totient is φ = 8186880.

The previous prime is 31640407. The next prime is 31640437. The reversal of 31640430 is 3404613.

31640430 = 425² + 426² + ... + 555².

It is a super-2 number, since 2×31640430² = 2002233621169800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 31640397 and 31640406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31640437) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 241465 + ... + 241595.

It is an arithmetic number, because the mean of its divisors is an integer number (1222452).

Almost surely, 2^31640430 is an apocalyptic number.

31640430 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

31640430 is an abundant number, since it is smaller than the sum of its proper divisors (46596498).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31640430 is a wasteful number, since it uses less digits than its factorization.

31640430 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 321.

The product of its (nonzero) digits is 864, while the sum is 21.

The square root of 31640430 is about 5624.9826666400. The cubic root of 31640430 is about 316.2865997313.

The spelling of 31640430 in words is "thirty-one million, six hundred forty thousand, four hundred thirty".