31779961 has 4 divisors (see below), whose sum is σ = 32555124. Its totient is φ = 31004800.

The previous prime is 31779949. The next prime is 31779971. The reversal of 31779961 is 16997713.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16997713 = 23 ⋅739031.

It can be written as a sum of positive squares in 2 ways, for example, as 13461561 + 18318400 = 3669^2 + 4280^2 .

It is a cyclic number.

It is not a de Polignac number, because 31779961 - 2²³ = 23391353 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31779901) 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, 387520 + ... + 387601.

It is an arithmetic number, because the mean of its divisors is an integer number (8138781).

Almost surely, 2^31779961 is an apocalyptic number.

It is an amenable number.

31779961 is a deficient number, since it is larger than the sum of its proper divisors (775163).

31779961 is an equidigital number, since it uses as much as digits as its factorization.

31779961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 775162.

The product of its digits is 71442, while the sum is 43.

The square root of 31779961 is about 5637.3718167245. The cubic root of 31779961 is about 316.7508482874.

The spelling of 31779961 in words is "thirty-one million, seven hundred seventy-nine thousand, nine hundred sixty-one".