78181649 has 16 divisors (see below), whose sum is σ = 97087872. Its totient is φ = 61302528.

The previous prime is 78181627. The next prime is 78181661. The reversal of 78181649 is 94618187.

It is not a de Polignac number, because 78181649 - 2¹² = 78177553 is a prime.

It is a super-2 number, since 2×78181649² = 12224740480718402, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78181679) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6482 + ... + 14084.

It is an arithmetic number, because the mean of its divisors is an integer number (6067992).

Almost surely, 2^78181649 is an apocalyptic number.

It is an amenable number.

78181649 is a deficient number, since it is larger than the sum of its proper divisors (18906223).

78181649 is a wasteful number, since it uses less digits than its factorization.

78181649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7736.

The product of its digits is 96768, while the sum is 44.

The square root of 78181649 is about 8842.0387354953. The cubic root of 78181649 is about 427.5972880276.

The spelling of 78181649 in words is "seventy-eight million, one hundred eighty-one thousand, six hundred forty-nine".