731125821 has 4 divisors (see below), whose sum is σ = 974834432. Its totient is φ = 487417212.

The previous prime is 731125819. The next prime is 731125849. The reversal of 731125821 is 128521137.

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.

It is not a de Polignac number, because 731125821 - 2¹ = 731125819 is a prime.

It is a super-2 number, since 2×731125821² = 1069089932265848082, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (731125891) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 121854301 + ... + 121854306.

It is an arithmetic number, because the mean of its divisors is an integer number (243708608).

Almost surely, 2^731125821 is an apocalyptic number.

It is an amenable number.

731125821 is a deficient number, since it is larger than the sum of its proper divisors (243708611).

731125821 is a wasteful number, since it uses less digits than its factorization.

731125821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243708610.

The product of its digits is 3360, while the sum is 30.

The square root of 731125821 is about 27039.3383979712. The cubic root of 731125821 is about 900.8739744805.

Adding to 731125821 its reverse (128521137), we get a palindrome (859646958).

The spelling of 731125821 in words is "seven hundred thirty-one million, one hundred twenty-five thousand, eight hundred twenty-one".