672211821 has 4 divisors (see below), whose sum is σ = 896282432. Its totient is φ = 448141212.

The previous prime is 672211783. The next prime is 672211877. The reversal of 672211821 is 128112276.

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 672211821 - 2¹¹ = 672209773 is a prime.

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 (672213821) 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, 112035301 + ... + 112035306.

It is an arithmetic number, because the mean of its divisors is an integer number (224070608).

Almost surely, 2^672211821 is an apocalyptic number.

It is an amenable number.

672211821 is a deficient number, since it is larger than the sum of its proper divisors (224070611).

672211821 is a wasteful number, since it uses less digits than its factorization.

672211821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 224070610.

The product of its digits is 2688, while the sum is 30.

The square root of 672211821 is about 25927.0480579645. The cubic root of 672211821 is about 875.9958494726.

The spelling of 672211821 in words is "six hundred seventy-two million, two hundred eleven thousand, eight hundred twenty-one".