78516021 has 8 divisors (see below), whose sum is σ = 108298080. Its totient is φ = 50538992.

The previous prime is 78516007. The next prime is 78516071. The reversal of 78516021 is 12061587.

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 78516021 - 2¹⁴ = 78499637 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 78516021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78516071) 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, 451155 + ... + 451328.

It is an arithmetic number, because the mean of its divisors is an integer number (13537260).

Almost surely, 2^78516021 is an apocalyptic number.

It is an amenable number.

78516021 is a deficient number, since it is larger than the sum of its proper divisors (29782059).

78516021 is a wasteful number, since it uses less digits than its factorization.

78516021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 902515.

The product of its (nonzero) digits is 3360, while the sum is 30.

The square root of 78516021 is about 8860.9266445446. The cubic root of 78516021 is about 428.2060123462.

The spelling of 78516021 in words is "seventy-eight million, five hundred sixteen thousand, twenty-one".