78021057 has 8 divisors (see below), whose sum is σ = 104098176. Its totient is φ = 51978992.

The previous prime is 78021043. The next prime is 78021061. The reversal of 78021057 is 75012087.

It is a happy number.

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 78021057 - 2¹¹ = 78019009 is a prime.

It is not an unprimeable number, because it can be changed into a prime (78021067) 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, 3033 + ... + 12854.

It is an arithmetic number, because the mean of its divisors is an integer number (13012272).

Almost surely, 2^78021057 is an apocalyptic number.

It is an amenable number.

78021057 is a deficient number, since it is larger than the sum of its proper divisors (26077119).

78021057 is a wasteful number, since it uses less digits than its factorization.

78021057 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17527.

The product of its (nonzero) digits is 3920, while the sum is 30.

The square root of 78021057 is about 8832.9529037576. The cubic root of 78021057 is about 427.3043131608.

The spelling of 78021057 in words is "seventy-eight million, twenty-one thousand, fifty-seven".