1621203999 has 8 divisors (see below), whose sum is σ = 2161925040. Its totient is φ = 1080642816.

The previous prime is 1621203953. The next prime is 1621204009. The reversal of 1621203999 is 9993021261.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1621203999 - 2⁸ = 1621203743 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1621203999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1621203299) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13864 + ... + 58605.

It is an arithmetic number, because the mean of its divisors is an integer number (270240630).

Almost surely, 2^1621203999 is an apocalyptic number.

1621203999 is a deficient number, since it is larger than the sum of its proper divisors (540721041).

1621203999 is an equidigital number, since it uses as much as digits as its factorization.

1621203999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79929.

The product of its (nonzero) digits is 52488, while the sum is 42.

The square root of 1621203999 is about 40264.1776148477. The cubic root of 1621203999 is about 1174.7511768878.

The spelling of 1621203999 in words is "one billion, six hundred twenty-one million, two hundred three thousand, nine hundred ninety-nine".