77948681 has 2 divisors, whose sum is σ = 77948682. Its totient is φ = 77948680.

The previous prime is 77948653. The next prime is 77948683. The reversal of 77948681 is 18684977.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 74304400 + 3644281 = 8620^2 + 1909^2 .

It is a cyclic number.

It is not a de Polignac number, because 77948681 - 2²² = 73754377 is a prime.

It is a super-2 number, since 2×77948681² = 12151993739279522, which contains 22 as substring.

Together with 77948683, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (77948683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38974340 + 38974341.

It is an arithmetic number, because the mean of its divisors is an integer number (38974341).

Almost surely, 2^77948681 is an apocalyptic number.

It is an amenable number.

77948681 is a deficient number, since it is larger than the sum of its proper divisors (1).

77948681 is an equidigital number, since it uses as much as digits as its factorization.

77948681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 677376, while the sum is 50.

The square root of 77948681 is about 8828.8550220286. The cubic root of 77948681 is about 427.1721430943.

The spelling of 77948681 in words is "seventy-seven million, nine hundred forty-eight thousand, six hundred eighty-one".