61779521 has 2 divisors, whose sum is σ = 61779522. Its totient is φ = 61779520.

The previous prime is 61779517. The next prime is 61779539. The reversal of 61779521 is 12597716.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 50922496 + 10857025 = 7136^2 + 3295^2 .

It is a cyclic number.

It is not a de Polignac number, because 61779521 - 2² = 61779517 is a prime.

It is not a weakly prime, because it can be changed into another prime (61779121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30889760 + 30889761.

It is an arithmetic number, because the mean of its divisors is an integer number (30889761).

Almost surely, 2^61779521 is an apocalyptic number.

It is an amenable number.

61779521 is a deficient number, since it is larger than the sum of its proper divisors (1).

61779521 is an equidigital number, since it uses as much as digits as its factorization.

61779521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 26460, while the sum is 38.

The square root of 61779521 is about 7859.9949745531. The cubic root of 61779521 is about 395.3194467609.

The spelling of 61779521 in words is "sixty-one million, seven hundred seventy-nine thousand, five hundred twenty-one".