78970921 has 4 divisors (see below), whose sum is σ = 79032832. Its totient is φ = 78909012.

The previous prime is 78970909. The next prime is 78970939. The reversal of 78970921 is 12907987.

It is a happy number.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12907987 = 29 ⋅445103.

It is a cyclic number.

It is not a de Polignac number, because 78970921 - 2¹³ = 78962729 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78970121) 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, 29001 + ... + 31606.

It is an arithmetic number, because the mean of its divisors is an integer number (19758208).

Almost surely, 2^78970921 is an apocalyptic number.

It is an amenable number.

78970921 is a deficient number, since it is larger than the sum of its proper divisors (61911).

78970921 is a wasteful number, since it uses less digits than its factorization.

78970921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61910.

The product of its (nonzero) digits is 63504, while the sum is 43.

The square root of 78970921 is about 8886.5584452025. The cubic root of 78970921 is about 429.0313892591.

The spelling of 78970921 in words is "seventy-eight million, nine hundred seventy thousand, nine hundred twenty-one".