992639821 has 4 divisors (see below), whose sum is σ = 1015724512. Its totient is φ = 969555132.

The previous prime is 992639801. The next prime is 992639831. The reversal of 992639821 is 128936299.

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 a cyclic number.

It is not a de Polignac number, because 992639821 - 2¹⁷ = 992508749 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (992639801) 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, 11542281 + ... + 11542366.

It is an arithmetic number, because the mean of its divisors is an integer number (253931128).

Almost surely, 2^992639821 is an apocalyptic number.

It is an amenable number.

992639821 is a deficient number, since it is larger than the sum of its proper divisors (23084691).

992639821 is a wasteful number, since it uses less digits than its factorization.

992639821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23084690.

The product of its digits is 419904, while the sum is 49.

The square root of 992639821 is about 31506.1870273126. The cubic root of 992639821 is about 997.5405631292.

The spelling of 992639821 in words is "nine hundred ninety-two million, six hundred thirty-nine thousand, eight hundred twenty-one".