31400981 has 4 divisors (see below), whose sum is σ = 31452492. Its totient is φ = 31349472.

The previous prime is 31400959. The next prime is 31400983. The reversal of 31400981 is 18900413.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 320356 + 31080625 = 566^2 + 5575^2 .

It is a cyclic number.

It is not a de Polignac number, because 31400981 - 2¹⁴ = 31384597 is a prime.

It is a super-2 number, since 2×31400981² = 1972043215524722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 31400981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31400983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24830 + ... + 26063.

It is an arithmetic number, because the mean of its divisors is an integer number (7863123).

Almost surely, 2^31400981 is an apocalyptic number.

It is an amenable number.

31400981 is a deficient number, since it is larger than the sum of its proper divisors (51511).

31400981 is an equidigital number, since it uses as much as digits as its factorization.

31400981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51510.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 31400981 is about 5603.6578232437. The cubic root of 31400981 is about 315.4867121018.

The spelling of 31400981 in words is "thirty-one million, four hundred thousand, nine hundred eighty-one".