791721 has 32 divisors (see below), whose sum is σ = 1382400. Its totient is φ = 438480.

The previous prime is 791699. The next prime is 791773. The reversal of 791721 is 127197.

It is not a de Polignac number, because 791721 - 2⁶ = 791657 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

791721 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (791321) 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, 11116 + ... + 11186.

It is an arithmetic number, because the mean of its divisors is an integer number (43200).

2⁷⁹¹⁷²¹ is an apocalyptic number.

791721 is a gapful number since it is divisible by the number (71) formed by its first and last digit.

It is an amenable number.

791721 is a deficient number, since it is larger than the sum of its proper divisors (590679).

791721 is a wasteful number, since it uses less digits than its factorization.

791721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146 (or 140 counting only the distinct ones).

The product of its digits is 882, while the sum is 27.

The square root of 791721 is about 889.7870531762. The cubic root of 791721 is about 92.5104346641.

The spelling of 791721 in words is "seven hundred ninety-one thousand, seven hundred twenty-one".