21221292 has 12 divisors (see below), whose sum is σ = 49516376. Its totient is φ = 7073760.

The previous prime is 21221279. The next prime is 21221293. The reversal of 21221292 is 29212212.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (12).

It is not an unprimeable number, because it can be changed into a prime (21221293) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 884209 + ... + 884232.

Almost surely, 2^21221292 is an apocalyptic number.

It is an amenable number.

21221292 is an abundant number, since it is smaller than the sum of its proper divisors (28295084).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21221292 is a wasteful number, since it uses less digits than its factorization.

21221292 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1768448 (or 1768446 counting only the distinct ones).

The product of its digits is 288, while the sum is 21.

The square root of 21221292 is about 4606.6573564788. The cubic root of 21221292 is about 276.8581252465.

The spelling of 21221292 in words is "twenty-one million, two hundred twenty-one thousand, two hundred ninety-two".