721634831 has 4 divisors (see below), whose sum is σ = 721997112. Its totient is φ = 721272552.

The previous prime is 721634813. The next prime is 721634843. The reversal of 721634831 is 138436127.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 721634831 - 2¹⁰ = 721633807 is a prime.

It is a super-2 number, since 2×721634831² = 1041513658624797122, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 721634791 and 721634800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721634861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 178136 + ... + 182141.

It is an arithmetic number, because the mean of its divisors is an integer number (180499278).

Almost surely, 2^721634831 is an apocalyptic number.

721634831 is a deficient number, since it is larger than the sum of its proper divisors (362281).

721634831 is a wasteful number, since it uses less digits than its factorization.

721634831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 362280.

The product of its digits is 24192, while the sum is 35.

The square root of 721634831 is about 26863.2617341975. The cubic root of 721634831 is about 896.9588012863.

The spelling of 721634831 in words is "seven hundred twenty-one million, six hundred thirty-four thousand, eight hundred thirty-one".