21908619 has 6 divisors (see below), whose sum is σ = 31645796. Its totient is φ = 14605740.

The previous prime is 21908611. The next prime is 21908651. The reversal of 21908619 is 91680912.

It is not a de Polignac number, because 21908619 - 2³ = 21908611 is a prime.

It is a super-2 number, since 2×21908619² = 959975172974322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21908611) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1217137 + ... + 1217154.

Almost surely, 2^21908619 is an apocalyptic number.

21908619 is a deficient number, since it is larger than the sum of its proper divisors (9737177).

21908619 is a wasteful number, since it uses less digits than its factorization.

21908619 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2434297 (or 2434294 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 36.

The square root of 21908619 is about 4680.6643759193. The cubic root of 21908619 is about 279.8154353420.

The spelling of 21908619 in words is "twenty-one million, nine hundred eight thousand, six hundred nineteen".