21197619 has 24 divisors (see below), whose sum is σ = 32165952. Its totient is φ = 13948200.

The previous prime is 21197593. The next prime is 21197621. The reversal of 21197619 is 91679112.

21197619 is a `hidden beast` number, since 21 + 19 + 7 + 619 = 666.

It is not a de Polignac number, because 21197619 - 2²⁰ = 20149043 is a prime.

It is a super-2 number, since 2×21197619² = 898678102538322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21197699) 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 23 ways as a sum of consecutive naturals, for example, 19644 + ... + 20694.

It is an arithmetic number, because the mean of its divisors is an integer number (1340248).

Almost surely, 2^21197619 is an apocalyptic number.

21197619 is a deficient number, since it is larger than the sum of its proper divisors (10968333).

21197619 is an equidigital number, since it uses as much as digits as its factorization.

21197619 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1149 (or 1137 counting only the distinct ones).

The product of its digits is 6804, while the sum is 36.

The square root of 21197619 is about 4604.0872059508. The cubic root of 21197619 is about 276.7551390413.

The spelling of 21197619 in words is "twenty-one million, one hundred ninety-seven thousand, six hundred nineteen".