31987481 has 8 divisors (see below), whose sum is σ = 32309640. Its totient is φ = 31667328.

The previous prime is 31987477. The next prime is 31987511. The reversal of 31987481 is 18478913.

It can be written as a sum of positive squares in 4 ways, for example, as 23921881 + 8065600 = 4891^2 + 2840^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 31987481 - 2² = 31987477 is a prime.

It is a super-2 number, since 2×31987481² = 2046397881450722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31987451) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 78005 + ... + 78413.

It is an arithmetic number, because the mean of its divisors is an integer number (4038705).

Almost surely, 2^31987481 is an apocalyptic number.

It is an amenable number.

31987481 is a deficient number, since it is larger than the sum of its proper divisors (322159).

31987481 is a wasteful number, since it uses less digits than its factorization.

31987481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1003.

The product of its digits is 48384, while the sum is 41.

The square root of 31987481 is about 5655.7476075228. The cubic root of 31987481 is about 317.4388035898.

The spelling of 31987481 in words is "thirty-one million, nine hundred eighty-seven thousand, four hundred eighty-one".