31055561 has 4 divisors (see below), whose sum is σ = 31148052. Its totient is φ = 30963072.

The previous prime is 31055551. The next prime is 31055567. The reversal of 31055561 is 16555013.

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 15405625 + 15649936 = 3925^2 + 3956^2 .

It is a cyclic number.

It is not a de Polignac number, because 31055561 - 2²² = 26861257 is a prime.

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 31055561.

It is not an unprimeable number, because it can be changed into a prime (31055567) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45740 + ... + 46413.

It is an arithmetic number, because the mean of its divisors is an integer number (7787013).

Almost surely, 2^31055561 is an apocalyptic number.

It is an amenable number.

31055561 is a deficient number, since it is larger than the sum of its proper divisors (92491).

31055561 is an equidigital number, since it uses as much as digits as its factorization.

31055561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92490.

The product of its (nonzero) digits is 2250, while the sum is 26.

The square root of 31055561 is about 5572.7516542548. The cubic root of 31055561 is about 314.3256287657.

The spelling of 31055561 in words is "thirty-one million, fifty-five thousand, five hundred sixty-one".