719981721 has 6 divisors (see below), whose sum is σ = 1039973610. Its totient is φ = 479987808.

The previous prime is 719981711. The next prime is 719981729. The reversal of 719981721 is 127189917.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 518199696 + 201782025 = 22764^2 + 14205^2 .

It is not a de Polignac number, because 719981721 - 2⁶ = 719981657 is a prime.

It is not an unprimeable number, because it can be changed into a prime (719981729) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 39998976 + ... + 39998993.

It is an arithmetic number, because the mean of its divisors is an integer number (173328935).

Almost surely, 2^719981721 is an apocalyptic number.

It is an amenable number.

719981721 is a deficient number, since it is larger than the sum of its proper divisors (319991889).

719981721 is a wasteful number, since it uses less digits than its factorization.

719981721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79997975 (or 79997972 counting only the distinct ones).

The product of its digits is 63504, while the sum is 45.

The square root of 719981721 is about 26832.4751187810. The cubic root of 719981721 is about 896.2733644697.

The spelling of 719981721 in words is "seven hundred nineteen million, nine hundred eighty-one thousand, seven hundred twenty-one".