31402240 has 36 divisors (see below), whose sum is σ = 75221244. Its totient is φ = 12560384.

The previous prime is 31402223. The next prime is 31402243. The reversal of 31402240 is 4220413.

It can be written as a sum of positive squares in 2 ways, for example, as 4528384 + 26873856 = 2128^2 + 5184^2 .

It is a super-2 number, since 2×31402240² = 1972201354035200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is not an unprimeable number, because it can be changed into a prime (31402243) 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 3 ways as a sum of consecutive naturals, for example, 10987 + ... + 13546.

It is an arithmetic number, because the mean of its divisors is an integer number (2089479).

Almost surely, 2^31402240 is an apocalyptic number.

It is an amenable number.

31402240 is an abundant number, since it is smaller than the sum of its proper divisors (43819004).

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

31402240 is an equidigital number, since it uses as much as digits as its factorization.

31402240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24554 (or 24540 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 31402240 is about 5603.7701594552. The cubic root of 31402240 is about 315.4909284506.

Adding to 31402240 its reverse (4220413), we get a palindrome (35622653).

The spelling of 31402240 in words is "thirty-one million, four hundred two thousand, two hundred forty".