21292155 has 12 divisors (see below), whose sum is σ = 36906480. Its totient is φ = 11355792.

The previous prime is 21292153. The next prime is 21292163. The reversal of 21292155 is 55129212.

It is not a de Polignac number, because 21292155 - 2¹ = 21292153 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21292153) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 236535 + ... + 236624.

It is an arithmetic number, because the mean of its divisors is an integer number (3075540).

Almost surely, 2^21292155 is an apocalyptic number.

21292155 is a deficient number, since it is larger than the sum of its proper divisors (15614325).

21292155 is a wasteful number, since it uses less digits than its factorization.

21292155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 473170 (or 473167 counting only the distinct ones).

The product of its digits is 1800, while the sum is 27.

The square root of 21292155 is about 4614.3423150000. The cubic root of 21292155 is about 277.1659481669.

The spelling of 21292155 in words is "twenty-one million, two hundred ninety-two thousand, one hundred fifty-five".