77291681 has 2 divisors, whose sum is σ = 77291682. Its totient is φ = 77291680.

The previous prime is 77291659. The next prime is 77291689. The reversal of 77291681 is 18619277.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 77281681 + 10000 = 8791^2 + 100^2 .

It is an emirp because it is prime and its reverse (18619277) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77291681 - 2²⁶ = 10182817 is a prime.

It is a super-2 number, since 2×77291681² = 11948007903611522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (77291689) 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, 38645840 + 38645841.

It is an arithmetic number, because the mean of its divisors is an integer number (38645841).

Almost surely, 2^77291681 is an apocalyptic number.

It is an amenable number.

77291681 is a deficient number, since it is larger than the sum of its proper divisors (1).

77291681 is an equidigital number, since it uses as much as digits as its factorization.

77291681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 42336, while the sum is 41.

The square root of 77291681 is about 8791.5687451103. The cubic root of 77291681 is about 425.9685977573.

The spelling of 77291681 in words is "seventy-seven million, two hundred ninety-one thousand, six hundred eighty-one".