21132278 has 4 divisors (see below), whose sum is σ = 31698420. Its totient is φ = 10566138.

The previous prime is 21132277. The next prime is 21132289. The reversal of 21132278 is 87223112.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21132277) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5283068 + ... + 5283071.

It is an arithmetic number, because the mean of its divisors is an integer number (7924605).

Almost surely, 2^21132278 is an apocalyptic number.

21132278 is a deficient number, since it is larger than the sum of its proper divisors (10566142).

21132278 is a wasteful number, since it uses less digits than its factorization.

21132278 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10566141.

The product of its digits is 1344, while the sum is 26.

The square root of 21132278 is about 4596.9857515550. The cubic root of 21132278 is about 276.4704833293.

The spelling of 21132278 in words is "twenty-one million, one hundred thirty-two thousand, two hundred seventy-eight".