21298155 has 8 divisors (see below), whose sum is σ = 34077072. Its totient is φ = 11359008.

The previous prime is 21298153. The next prime is 21298159. The reversal of 21298155 is 55189212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21298155 - 2¹ = 21298153 is a prime.

It is a super-2 number, since 2×21298155² = 907222812808050, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21298153) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 709924 + ... + 709953.

It is an arithmetic number, because the mean of its divisors is an integer number (4259634).

Almost surely, 2^21298155 is an apocalyptic number.

21298155 is a deficient number, since it is larger than the sum of its proper divisors (12778917).

21298155 is a wasteful number, since it uses less digits than its factorization.

21298155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1419885.

The product of its digits is 7200, while the sum is 33.

The square root of 21298155 is about 4614.9924160284. The cubic root of 21298155 is about 277.1919802823.

The spelling of 21298155 in words is "twenty-one million, two hundred ninety-eight thousand, one hundred fifty-five".