21519690 has 16 divisors (see below), whose sum is σ = 51647328. Its totient is φ = 5738576.

The previous prime is 21519683. The next prime is 21519691. The reversal of 21519690 is 9691512.

It is a super-2 number, since 2×21519690² = 926194115392200, which contains 22 as substring.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (21519691) 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, 358632 + ... + 358691.

It is an arithmetic number, because the mean of its divisors is an integer number (3227958).

Almost surely, 2^21519690 is an apocalyptic number.

21519690 is an abundant number, since it is smaller than the sum of its proper divisors (30127638).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21519690 is a wasteful number, since it uses less digits than its factorization.

21519690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 717333.

The product of its (nonzero) digits is 4860, while the sum is 33.

The square root of 21519690 is about 4638.9319891544. The cubic root of 21519690 is about 278.1497476611.

The spelling of 21519690 in words is "twenty-one million, five hundred nineteen thousand, six hundred ninety".