721372137 has 8 divisors (see below), whose sum is σ = 970654080. Its totient is φ = 476502480.

The previous prime is 721372123. The next prime is 721372151. The reversal of 721372137 is 731273127.

It is an interprime number because it is at equal distance from previous prime (721372123) and next prime (721372151).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 721372137 - 2⁶ = 721372073 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 721372098 and 721372107.

It is not an unprimeable number, because it can be changed into a prime (721372117) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1102689 + ... + 1103342.

It is an arithmetic number, because the mean of its divisors is an integer number (121331760).

Almost surely, 2^721372137 is an apocalyptic number.

It is an amenable number.

721372137 is a deficient number, since it is larger than the sum of its proper divisors (249281943).

721372137 is a wasteful number, since it uses less digits than its factorization.

721372137 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2206143.

The product of its digits is 12348, while the sum is 33.

The square root of 721372137 is about 26858.3718233254. The cubic root of 721372137 is about 896.8499492362.

The spelling of 721372137 in words is "seven hundred twenty-one million, three hundred seventy-two thousand, one hundred thirty-seven".