78953721 has 32 divisors (see below), whose sum is σ = 138163200. Its totient is φ = 38854080.

The previous prime is 78953717. The next prime is 78953731. The reversal of 78953721 is 12735987.

It is not a de Polignac number, because 78953721 - 2² = 78953717 is a prime.

It is not an unprimeable number, because it can be changed into a prime (78953731) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4606 + ... + 13383.

It is an arithmetic number, because the mean of its divisors is an integer number (4317600).

Almost surely, 2^78953721 is an apocalyptic number.

It is an amenable number.

78953721 is a deficient number, since it is larger than the sum of its proper divisors (59209479).

78953721 is a wasteful number, since it uses less digits than its factorization.

78953721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18029.

The product of its digits is 105840, while the sum is 42.

The square root of 78953721 is about 8885.5906387814. The cubic root of 78953721 is about 429.0002390770. Note that the first 3 decimals are identical.

The spelling of 78953721 in words is "seventy-eight million, nine hundred fifty-three thousand, seven hundred twenty-one".