21519019 has 4 divisors (see below), whose sum is σ = 21566160. Its totient is φ = 21471880.

The previous prime is 21518971. The next prime is 21519061. The reversal of 21519019 is 91091512.

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 21519019 - 2¹⁵ = 21486251 is a prime.

It is a super-2 number, since 2×21519019² = 926136357444722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21519079) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22879 + ... + 23800.

It is an arithmetic number, because the mean of its divisors is an integer number (5391540).

Almost surely, 2^21519019 is an apocalyptic number.

21519019 is a deficient number, since it is larger than the sum of its proper divisors (47141).

21519019 is an equidigital number, since it uses as much as digits as its factorization.

21519019 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47140.

The product of its (nonzero) digits is 810, while the sum is 28.

The square root of 21519019 is about 4638.8596659093. The cubic root of 21519019 is about 278.1468566588.

The spelling of 21519019 in words is "twenty-one million, five hundred nineteen thousand, nineteen".