78621857 has 8 divisors (see below), whose sum is σ = 79632384. Its totient is φ = 77616288.

The previous prime is 78621839. The next prime is 78621911. The reversal of 78621857 is 75812687.

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 78621857 - 2⁶ = 78621793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78621817) 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, 38453 + ... + 40445.

It is an arithmetic number, because the mean of its divisors is an integer number (9954048).

Almost surely, 2^78621857 is an apocalyptic number.

It is an amenable number.

78621857 is a deficient number, since it is larger than the sum of its proper divisors (1010527).

78621857 is a wasteful number, since it uses less digits than its factorization.

78621857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2479.

The product of its digits is 188160, while the sum is 44.

The square root of 78621857 is about 8866.8966950112. The cubic root of 78621857 is about 428.3983266589.

The spelling of 78621857 in words is "seventy-eight million, six hundred twenty-one thousand, eight hundred fifty-seven".