61917521 has 2 divisors, whose sum is σ = 61917522. Its totient is φ = 61917520.

The previous prime is 61917517. The next prime is 61917547. The reversal of 61917521 is 12571916.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 57760000 + 4157521 = 7600^2 + 2039^2 .

It is a cyclic number.

It is not a de Polignac number, because 61917521 - 2² = 61917517 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (61917551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30958760 + 30958761.

It is an arithmetic number, because the mean of its divisors is an integer number (30958761).

Almost surely, 2^61917521 is an apocalyptic number.

It is an amenable number.

61917521 is a deficient number, since it is larger than the sum of its proper divisors (1).

61917521 is an equidigital number, since it uses as much as digits as its factorization.

61917521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3780, while the sum is 32.

The square root of 61917521 is about 7868.7687092708. The cubic root of 61917521 is about 395.6135761264.

The spelling of 61917521 in words is "sixty-one million, nine hundred seventeen thousand, five hundred twenty-one".