21293155 has 24 divisors (see below), whose sum is σ = 28038528. Its totient is φ = 15515136.

The previous prime is 21293141. The next prime is 21293191. The reversal of 21293155 is 55139212.

It is a de Polignac number, because none of the positive numbers 2^k-21293155 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 23 ways as a sum of consecutive naturals, for example, 95374 + ... + 95596.

It is an arithmetic number, because the mean of its divisors is an integer number (1168272).

Almost surely, 2^21293155 is an apocalyptic number.

21293155 is a deficient number, since it is larger than the sum of its proper divisors (6745373).

21293155 is a wasteful number, since it uses less digits than its factorization.

21293155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 367 (or 354 counting only the distinct ones).

The product of its digits is 2700, while the sum is 28.

The square root of 21293155 is about 4614.4506715318. The cubic root of 21293155 is about 277.1702871924.

The spelling of 21293155 in words is "twenty-one million, two hundred ninety-three thousand, one hundred fifty-five".