78787669 has 2 divisors, whose sum is σ = 78787670. Its totient is φ = 78787668.

The previous prime is 78787663. The next prime is 78787697. The reversal of 78787669 is 96678787.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 67864644 + 10923025 = 8238^2 + 3305^2 .

It is a cyclic number.

It is not a de Polignac number, because 78787669 - 2⁹ = 78787157 is a prime.

It is a super-2 number, since 2×78787669² = 12414993572907122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78787663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39393834 + 39393835.

It is an arithmetic number, because the mean of its divisors is an integer number (39393835).

Almost surely, 2^78787669 is an apocalyptic number.

It is an amenable number.

78787669 is a deficient number, since it is larger than the sum of its proper divisors (1).

78787669 is an equidigital number, since it uses as much as digits as its factorization.

78787669 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7112448, while the sum is 58.

The square root of 78787669 is about 8876.2418286119. The cubic root of 78787669 is about 428.6992764979.

The spelling of 78787669 in words is "seventy-eight million, seven hundred eighty-seven thousand, six hundred sixty-nine".