77501681 has 2 divisors, whose sum is σ = 77501682. Its totient is φ = 77501680.

The previous prime is 77501663. The next prime is 77501687. The reversal of 77501681 is 18610577.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 69889600 + 7612081 = 8360^2 + 2759^2 .

It is an emirp because it is prime and its reverse (18610577) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77501681 is a prime.

It is a super-2 number, since 2×77501681² = 12013021115651522, which contains 22 as substring.

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 (77501687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38750840 + 38750841.

It is an arithmetic number, because the mean of its divisors is an integer number (38750841).

Almost surely, 2^77501681 is an apocalyptic number.

It is an amenable number.

77501681 is a deficient number, since it is larger than the sum of its proper divisors (1).

77501681 is an equidigital number, since it uses as much as digits as its factorization.

77501681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11760, while the sum is 35.

The square root of 77501681 is about 8803.5039046961. The cubic root of 77501681 is about 426.3540317050.

The spelling of 77501681 in words is "seventy-seven million, five hundred one thousand, six hundred eighty-one".