31776561 has 6 divisors (see below), whose sum is σ = 45899490. Its totient is φ = 21184368.

The previous prime is 31776557. The next prime is 31776601. The reversal of 31776561 is 16567713.

It can be written as a sum of positive squares in only one way, i.e., 23824161 + 7952400 = 4881^2 + 2820^2 .

It is not a de Polignac number, because 31776561 - 2² = 31776557 is a prime.

It is not an unprimeable number, because it can be changed into a prime (31776551) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1765356 + ... + 1765373.

It is an arithmetic number, because the mean of its divisors is an integer number (7649915).

Almost surely, 2^31776561 is an apocalyptic number.

It is an amenable number.

31776561 is a deficient number, since it is larger than the sum of its proper divisors (14122929).

31776561 is a wasteful number, since it uses less digits than its factorization.

31776561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3530735 (or 3530732 counting only the distinct ones).

The product of its digits is 26460, while the sum is 36.

The square root of 31776561 is about 5637.0702496953. The cubic root of 31776561 is about 316.7395519520.

The spelling of 31776561 in words is "thirty-one million, seven hundred seventy-six thousand, five hundred sixty-one".