31405690 has 16 divisors (see below), whose sum is σ = 57114792. Its totient is φ = 12432384.

The previous prime is 31405687. The next prime is 31405691. The reversal of 31405690 is 9650413.

It can be written as a sum of positive squares in 4 ways, for example, as 26347689 + 5058001 = 5133^2 + 2249^2 .

It is a super-2 number, since 2×31405690² = 1972634728752200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (31405691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15219 + ... + 17158.

Almost surely, 2^31405690 is an apocalyptic number.

31405690 is a deficient number, since it is larger than the sum of its proper divisors (25709102).

31405690 is a wasteful number, since it uses less digits than its factorization.

31405690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32481.

The product of its (nonzero) digits is 3240, while the sum is 28.

The square root of 31405690 is about 5604.0779794717. The cubic root of 31405690 is about 315.5024818073.

The spelling of 31405690 in words is "thirty-one million, four hundred five thousand, six hundred ninety".