78462721 has 4 divisors (see below), whose sum is σ = 79456000. Its totient is φ = 77469444.

The previous prime is 78462707. The next prime is 78462731. The reversal of 78462721 is 12726487.

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: 12726487 = 241 ⋅52807.

It is a cyclic number.

It is not a de Polignac number, because 78462721 - 2⁵ = 78462689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78462731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 496521 + ... + 496678.

It is an arithmetic number, because the mean of its divisors is an integer number (19864000).

Almost surely, 2^78462721 is an apocalyptic number.

It is an amenable number.

78462721 is a deficient number, since it is larger than the sum of its proper divisors (993279).

78462721 is an equidigital number, since it uses as much as digits as its factorization.

78462721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 993278.

The product of its digits is 37632, while the sum is 37.

The square root of 78462721 is about 8857.9185478305. The cubic root of 78462721 is about 428.1090956210.

The spelling of 78462721 in words is "seventy-eight million, four hundred sixty-two thousand, seven hundred twenty-one".