721622537 has 4 divisors (see below), whose sum is σ = 736976256. Its totient is φ = 706268820.

The previous prime is 721622491. The next prime is 721622543. The reversal of 721622537 is 735226127.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 735226127 = 3019 ⋅243533.

It is a cyclic number.

It is not a de Polignac number, because 721622537 - 2¹⁰ = 721621513 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 721622497 and 721622506.

It is not an unprimeable number, because it can be changed into a prime (721622437) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7676789 + ... + 7676882.

It is an arithmetic number, because the mean of its divisors is an integer number (184244064).

Almost surely, 2^721622537 is an apocalyptic number.

It is an amenable number.

721622537 is a deficient number, since it is larger than the sum of its proper divisors (15353719).

721622537 is a wasteful number, since it uses less digits than its factorization.

721622537 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15353718.

The product of its digits is 35280, while the sum is 35.

The square root of 721622537 is about 26863.0329076968. The cubic root of 721622537 is about 896.9537076325.

The spelling of 721622537 in words is "seven hundred twenty-one million, six hundred twenty-two thousand, five hundred thirty-seven".