21641619 has 8 divisors (see below), whose sum is σ = 28879312. Its totient is φ = 14415840.

The previous prime is 21641611. The next prime is 21641671. The reversal of 21641619 is 91614612.

It is a happy number.

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

It is not a de Polignac number, because 21641619 - 2³ = 21641611 is a prime.

It is a super-2 number, since 2×21641619² = 936719345882322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21641611) 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, 2949 + ... + 7209.

It is an arithmetic number, because the mean of its divisors is an integer number (3609914).

Almost surely, 2^21641619 is an apocalyptic number.

21641619 is a deficient number, since it is larger than the sum of its proper divisors (7237693).

21641619 is a wasteful number, since it uses less digits than its factorization.

21641619 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5957.

The product of its digits is 2592, while the sum is 30.

The square root of 21641619 is about 4652.0553522072. The cubic root of 21641619 is about 278.6740840408.

The spelling of 21641619 in words is "twenty-one million, six hundred forty-one thousand, six hundred nineteen".