21640619 has 24 divisors (see below), whose sum is σ = 29233152. Its totient is φ = 15556320.

The previous prime is 21640613. The next prime is 21640621. The reversal of 21640619 is 91604612.

It is not a de Polignac number, because 21640619 - 2⁸ = 21640363 is a prime.

It is a super-2 number, since 2×21640619² = 936632781406322, which contains 22 as substring.

It is a hoax number, since the sum of its digits (29) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 21640591 and 21640600.

It is not an unprimeable number, because it can be changed into a prime (21640613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12182 + ... + 13844.

It is an arithmetic number, because the mean of its divisors is an integer number (1218048).

Almost surely, 2^21640619 is an apocalyptic number.

21640619 is a deficient number, since it is larger than the sum of its proper divisors (7592533).

21640619 is a wasteful number, since it uses less digits than its factorization.

21640619 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1707 (or 1694 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 21640619 is about 4651.9478715910. The cubic root of 21640619 is about 278.6697917191.

The spelling of 21640619 in words is "twenty-one million, six hundred forty thousand, six hundred nineteen".