78780921 has 8 divisors (see below), whose sum is σ = 105215040. Its totient is φ = 52433712.

The previous prime is 78780901. The next prime is 78780971. The reversal of 78780921 is 12908787.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 78780921 - 2⁶ = 78780857 is a prime.

It is not an unprimeable number, because it can be changed into a prime (78780901) 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, 19581 + ... + 23258.

It is an arithmetic number, because the mean of its divisors is an integer number (13151880).

Almost surely, 2^78780921 is an apocalyptic number.

It is an amenable number.

78780921 is a deficient number, since it is larger than the sum of its proper divisors (26434119).

78780921 is a wasteful number, since it uses less digits than its factorization.

78780921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43455.

The product of its (nonzero) digits is 56448, while the sum is 42.

The square root of 78780921 is about 8875.8617046459. The cubic root of 78780921 is about 428.6870370813.

The spelling of 78780921 in words is "seventy-eight million, seven hundred eighty thousand, nine hundred twenty-one".