21899138 has 4 divisors (see below), whose sum is σ = 32848710. Its totient is φ = 10949568.

The previous prime is 21899117. The next prime is 21899159. The reversal of 21899138 is 83199812.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21899117) and next prime (21899159).

It can be written as a sum of positive squares in only one way, i.e., 21279769 + 619369 = 4613^2 + 787^2 .

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21899095 and 21899104.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 5474783 + ... + 5474786.

Almost surely, 2^21899138 is an apocalyptic number.

21899138 is a deficient number, since it is larger than the sum of its proper divisors (10949572).

21899138 is a wasteful number, since it uses less digits than its factorization.

21899138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10949571.

The product of its digits is 31104, while the sum is 41.

The square root of 21899138 is about 4679.6514827495. The cubic root of 21899138 is about 279.7750659494.

The spelling of 21899138 in words is "twenty-one million, eight hundred ninety-nine thousand, one hundred thirty-eight".