78406591 has 8 divisors (see below), whose sum is σ = 79059024. Its totient is φ = 77757120.

The previous prime is 78406583. The next prime is 78406621. The reversal of 78406591 is 19560487.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 78406591 - 2³ = 78406583 is a prime.

It is a super-2 number, since 2×78406591² = 12295187024482562, 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 (78406511) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 102651 + ... + 103411.

It is an arithmetic number, because the mean of its divisors is an integer number (9882378).

Almost surely, 2^78406591 is an apocalyptic number.

78406591 is a deficient number, since it is larger than the sum of its proper divisors (652433).

78406591 is a wasteful number, since it uses less digits than its factorization.

78406591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1481.

The product of its (nonzero) digits is 60480, while the sum is 40.

The square root of 78406591 is about 8854.7496294362. The cubic root of 78406591 is about 428.0069855761.

The spelling of 78406591 in words is "seventy-eight million, four hundred six thousand, five hundred ninety-one".