77638969 has 2 divisors, whose sum is σ = 77638970. Its totient is φ = 77638968.

The previous prime is 77638963. The next prime is 77638993. The reversal of 77638969 is 96983677.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 67322025 + 10316944 = 8205^2 + 3212^2 .

It is a cyclic number.

It is not a de Polignac number, because 77638969 - 2⁵ = 77638937 is a prime.

It is a super-2 number, since 2×77638969² = 12055619014765922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (77638963) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38819484 + 38819485.

It is an arithmetic number, because the mean of its divisors is an integer number (38819485).

Almost surely, 2^77638969 is an apocalyptic number.

It is an amenable number.

77638969 is a deficient number, since it is larger than the sum of its proper divisors (1).

77638969 is an equidigital number, since it uses as much as digits as its factorization.

77638969 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3429216, while the sum is 55.

The square root of 77638969 is about 8811.2978045235. The cubic root of 77638969 is about 426.6056338345.

The spelling of 77638969 in words is "seventy-seven million, six hundred thirty-eight thousand, nine hundred sixty-nine".