721291493 has 12 divisors (see below), whose sum is σ = 784586880. Its totient is φ = 662787216.

The previous prime is 721291447. The next prime is 721291499. The reversal of 721291493 is 394192127.

It is not a de Polignac number, because 721291493 - 2⁶ = 721291429 is a prime.

It is a super-2 number, since 2×721291493² = 1040522835748338098, which contains 22 as substring.

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721291499) 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, 28118 + ... + 47256.

It is an arithmetic number, because the mean of its divisors is an integer number (65382240).

Almost surely, 2^721291493 is an apocalyptic number.

It is an amenable number.

721291493 is a deficient number, since it is larger than the sum of its proper divisors (63295387).

721291493 is a wasteful number, since it uses less digits than its factorization.

721291493 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19388 (or 19375 counting only the distinct ones).

The product of its digits is 27216, while the sum is 38.

The square root of 721291493 is about 26856.8704989989. The cubic root of 721291493 is about 896.8165276225.

The spelling of 721291493 in words is "seven hundred twenty-one million, two hundred ninety-one thousand, four hundred ninety-three".