31290381 has 12 divisors (see below), whose sum is σ = 46871552. Its totient is φ = 20860092.

The previous prime is 31290367. The next prime is 31290403. The reversal of 31290381 is 18309213.

It is not a de Polignac number, because 31290381 - 2⁶ = 31290317 is a prime.

It is a super-2 number, since 2×31290381² = 1958175886250322, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31290341) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 64141 + ... + 64626.

Almost surely, 2^31290381 is an apocalyptic number.

It is an amenable number.

31290381 is a deficient number, since it is larger than the sum of its proper divisors (15581171).

31290381 is an equidigital number, since it uses as much as digits as its factorization.

31290381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128782 (or 128770 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 31290381 is about 5593.7805641623. The cubic root of 31290381 is about 315.1158757361.

Adding to 31290381 its reverse (18309213), we get a palindrome (49599594).

The spelling of 31290381 in words is "thirty-one million, two hundred ninety thousand, three hundred eighty-one".