19621399 has 4 divisors (see below), whose sum is σ = 22424464. Its totient is φ = 16818336.

The previous prime is 19621367. The next prime is 19621403. The reversal of 19621399 is 99312691.

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 19621399 - 2⁵ = 19621367 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 (19621499) 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, 1401522 + ... + 1401535.

It is an arithmetic number, because the mean of its divisors is an integer number (5606116).

Almost surely, 2^19621399 is an apocalyptic number.

19621399 is a deficient number, since it is larger than the sum of its proper divisors (2803065).

19621399 is an equidigital number, since it uses as much as digits as its factorization.

19621399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2803064.

The product of its digits is 26244, while the sum is 40.

The square root of 19621399 is about 4429.6048356484. The cubic root of 19621399 is about 269.7180366929.

The spelling of 19621399 in words is "nineteen million, six hundred twenty-one thousand, three hundred ninety-nine".