21519969 has 8 divisors (see below), whose sum is σ = 28977792. Its totient is φ = 14204400.

The previous prime is 21519929. The next prime is 21520003. The reversal of 21519969 is 96991512.

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 21519969 - 2⁸ = 21519713 is a prime.

It is a super-2 number, since 2×21519969² = 926218131521922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21519969.

It is not an unprimeable number, because it can be changed into a prime (21519919) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35209 + ... + 35814.

It is an arithmetic number, because the mean of its divisors is an integer number (3622224).

Almost surely, 2^21519969 is an apocalyptic number.

It is an amenable number.

21519969 is a deficient number, since it is larger than the sum of its proper divisors (7457823).

21519969 is a wasteful number, since it uses less digits than its factorization.

21519969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71127.

The product of its digits is 43740, while the sum is 42.

The square root of 21519969 is about 4638.9620606338. The cubic root of 21519969 is about 278.1509497144.

The spelling of 21519969 in words is "twenty-one million, five hundred nineteen thousand, nine hundred sixty-nine".