78380661 has 4 divisors (see below), whose sum is σ = 104507552. Its totient is φ = 52253772.

The previous prime is 78380651. The next prime is 78380677. The reversal of 78380661 is 16608387.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 78380661 - 2⁵ = 78380629 is a prime.

It is a super-2 number, since 2×78380661² = 12287056037593842, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78380641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13063441 + ... + 13063446.

It is an arithmetic number, because the mean of its divisors is an integer number (26126888).

Almost surely, 2^78380661 is an apocalyptic number.

It is an amenable number.

78380661 is a deficient number, since it is larger than the sum of its proper divisors (26126891).

78380661 is a wasteful number, since it uses less digits than its factorization.

78380661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26126890.

The product of its (nonzero) digits is 48384, while the sum is 39.

The square root of 78380661 is about 8853.2853224100. The cubic root of 78380661 is about 427.9597980261.

The spelling of 78380661 in words is "seventy-eight million, three hundred eighty thousand, six hundred sixty-one".