61931257 has 2 divisors, whose sum is σ = 61931258. Its totient is φ = 61931256.

The previous prime is 61931239. The next prime is 61931263. The reversal of 61931257 is 75213916.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 57517056 + 4414201 = 7584^2 + 2101^2 .

It is a cyclic number.

It is not a de Polignac number, because 61931257 - 2¹¹ = 61929209 is a prime.

It is not a weakly prime, because it can be changed into another prime (61931237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30965628 + 30965629.

It is an arithmetic number, because the mean of its divisors is an integer number (30965629).

Almost surely, 2^61931257 is an apocalyptic number.

It is an amenable number.

61931257 is a deficient number, since it is larger than the sum of its proper divisors (1).

61931257 is an equidigital number, since it uses as much as digits as its factorization.

61931257 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11340, while the sum is 34.

The square root of 61931257 is about 7869.6414784919. The cubic root of 61931257 is about 395.6428287310.

It can be divided in two parts, 619312 and 57, that added together give a square (619369 = 787²).

The spelling of 61931257 in words is "sixty-one million, nine hundred thirty-one thousand, two hundred fifty-seven".