21921892 has 6 divisors (see below), whose sum is σ = 38363318. Its totient is φ = 10960944.

The previous prime is 21921869. The next prime is 21921899. The reversal of 21921892 is 29812912.

It can be written as a sum of positive squares in only one way, i.e., 19412836 + 2509056 = 4406^2 + 1584^2 .

It is not an unprimeable number, because it can be changed into a prime (21921899) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2740233 + ... + 2740240.

Almost surely, 2^21921892 is an apocalyptic number.

It is an amenable number.

21921892 is a deficient number, since it is larger than the sum of its proper divisors (16441426).

21921892 is a wasteful number, since it uses less digits than its factorization.

21921892 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5480477 (or 5480475 counting only the distinct ones).

The product of its digits is 5184, while the sum is 34.

The square root of 21921892 is about 4682.0820155140. The cubic root of 21921892 is about 279.8719312277.

The spelling of 21921892 in words is "twenty-one million, nine hundred twenty-one thousand, eight hundred ninety-two".