7678721 has 12 divisors (see below), whose sum is σ = 8104320. Its totient is φ = 7272720.

The previous prime is 7678709. The next prime is 7678733. The reversal of 7678721 is 1278767.

It is an interprime number because it is at equal distance from previous prime (7678709) and next prime (7678733).

It is not a de Polignac number, because 7678721 - 2¹⁴ = 7662337 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

Its product of digits (32928) is a multiple of the sum of its prime factors (224).

It is not an unprimeable number, because it can be changed into a prime (7678751) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 97160 + ... + 97238.

It is an arithmetic number, because the mean of its divisors is an integer number (675360).

Almost surely, 2^7678721 is an apocalyptic number.

7678721 is a gapful number since it is divisible by the number (71) formed by its first and last digit.

It is an amenable number.

7678721 is a deficient number, since it is larger than the sum of its proper divisors (425599).

7678721 is an equidigital number, since it uses as much as digits as its factorization.

7678721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 224 (or 187 counting only the distinct ones).

The product of its digits is 32928, while the sum is 38.

The square root of 7678721 is about 2771.0505228162. The cubic root of 7678721 is about 197.2860129591.

The spelling of 7678721 in words is "seven million, six hundred seventy-eight thousand, seven hundred twenty-one".