21892261 has 4 divisors (see below), whose sum is σ = 21902400. Its totient is φ = 21882124.

The previous prime is 21892253. The next prime is 21892267. The reversal of 21892261 is 16229812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21892261 - 2³ = 21892253 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21892267) 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 3 ways as a sum of consecutive naturals, for example, 391 + ... + 6628.

It is an arithmetic number, because the mean of its divisors is an integer number (5475600).

Almost surely, 2^21892261 is an apocalyptic number.

It is an amenable number.

21892261 is a deficient number, since it is larger than the sum of its proper divisors (10139).

21892261 is an equidigital number, since it uses as much as digits as its factorization.

21892261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10138.

The product of its digits is 3456, while the sum is 31.

The square root of 21892261 is about 4678.9166481142. The cubic root of 21892261 is about 279.7457769037.

The spelling of 21892261 in words is "twenty-one million, eight hundred ninety-two thousand, two hundred sixty-one".