31001881 has 2 divisors, whose sum is σ = 31001882. Its totient is φ = 31001880.

The previous prime is 31001857. The next prime is 31001903. The reversal of 31001881 is 18810013.

It is an a-pointer prime, because the next prime (31001903) can be obtained adding 31001881 to its sum of digits (22).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 29811600 + 1190281 = 5460^2 + 1091^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31001881 is a prime.

It is a super-2 number, since 2×31001881² = 1922233251076322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (31001851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15500940 + 15500941.

It is an arithmetic number, because the mean of its divisors is an integer number (15500941).

Almost surely, 2^31001881 is an apocalyptic number.

It is an amenable number.

31001881 is a deficient number, since it is larger than the sum of its proper divisors (1).

31001881 is an equidigital number, since it uses as much as digits as its factorization.

31001881 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192, while the sum is 22.

The square root of 31001881 is about 5567.9332790543. The cubic root of 31001881 is about 314.1444188063.

Adding to 31001881 its reverse (18810013), we get a palindrome (49811894).

The spelling of 31001881 in words is "thirty-one million, one thousand, eight hundred eighty-one".