61891657 has 2 divisors, whose sum is σ = 61891658. Its totient is φ = 61891656.

The previous prime is 61891633. The next prime is 61891693. The reversal of 61891657 is 75619816.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 31685641 + 30206016 = 5629^2 + 5496^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61891657 is a prime.

It is not a weakly prime, because it can be changed into another prime (61891457) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30945828 + 30945829.

It is an arithmetic number, because the mean of its divisors is an integer number (30945829).

Almost surely, 2^61891657 is an apocalyptic number.

It is an amenable number.

61891657 is a deficient number, since it is larger than the sum of its proper divisors (1).

61891657 is an equidigital number, since it uses as much as digits as its factorization.

61891657 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 90720, while the sum is 43.

The square root of 61891657 is about 7867.1250784515. The cubic root of 61891657 is about 395.5584836183.

The spelling of 61891657 in words is "sixty-one million, eight hundred ninety-one thousand, six hundred fifty-seven".