31192561 has 2 divisors, whose sum is σ = 31192562. Its totient is φ = 31192560.

The previous prime is 31192559. The next prime is 31192583. The reversal of 31192561 is 16529113.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 24561936 + 6630625 = 4956^2 + 2575^2 .

It is an emirp because it is prime and its reverse (16529113) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31192561 - 2¹ = 31192559 is a prime.

Together with 31192559, it forms a pair of twin primes.

It is equal to p_1927054 and since 31192561 and 1927054 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (31192261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15596280 + 15596281.

It is an arithmetic number, because the mean of its divisors is an integer number (15596281).

Almost surely, 2^31192561 is an apocalyptic number.

It is an amenable number.

31192561 is a deficient number, since it is larger than the sum of its proper divisors (1).

31192561 is an equidigital number, since it uses as much as digits as its factorization.

31192561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1620, while the sum is 28.

The square root of 31192561 is about 5585.0300804920. The cubic root of 31192561 is about 314.7871611684.

The spelling of 31192561 in words is "thirty-one million, one hundred ninety-two thousand, five hundred sixty-one".