78021973 has 4 divisors (see below), whose sum is σ = 78043680. Its totient is φ = 78000268.

The previous prime is 78021953. The next prime is 78021991. The reversal of 78021973 is 37912087.

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 a cyclic number.

It is not a de Polignac number, because 78021973 - 2⁵ = 78021941 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78021953) 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, 4033 + ... + 13126.

It is an arithmetic number, because the mean of its divisors is an integer number (19510920).

Almost surely, 2^78021973 is an apocalyptic number.

It is an amenable number.

78021973 is a deficient number, since it is larger than the sum of its proper divisors (21707).

78021973 is a wasteful number, since it uses less digits than its factorization.

78021973 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21706.

The product of its (nonzero) digits is 21168, while the sum is 37.

The square root of 78021973 is about 8833.0047548951. The cubic root of 78021973 is about 427.3059853983.

The spelling of 78021973 in words is "seventy-eight million, twenty-one thousand, nine hundred seventy-three".