31406381 has 2 divisors, whose sum is σ = 31406382. Its totient is φ = 31406380.

The previous prime is 31406363. The next prime is 31406393. The reversal of 31406381 is 18360413.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 22944100 + 8462281 = 4790^2 + 2909^2 .

It is a cyclic number.

It is not a de Polignac number, because 31406381 - 2¹⁰ = 31405357 is a prime.

It is a super-2 number, since 2×31406381² = 1972721535034322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 31406381.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31406281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15703190 + 15703191.

It is an arithmetic number, because the mean of its divisors is an integer number (15703191).

Almost surely, 2^31406381 is an apocalyptic number.

It is an amenable number.

31406381 is a deficient number, since it is larger than the sum of its proper divisors (1).

31406381 is an equidigital number, since it uses as much as digits as its factorization.

31406381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 31406381 is about 5604.1396306659. The cubic root of 31406381 is about 315.5047957258.

Adding to 31406381 its reverse (18360413), we get a palindrome (49766794).

The spelling of 31406381 in words is "thirty-one million, four hundred six thousand, three hundred eighty-one".