21682155 has 32 divisors (see below), whose sum is σ = 38055168. Its totient is φ = 10454400.

The previous prime is 21682151. The next prime is 21682163. The reversal of 21682155 is 55128612.

It is not a de Polignac number, because 21682155 - 2² = 21682151 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21682151) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 54417 + ... + 54813.

It is an arithmetic number, because the mean of its divisors is an integer number (1189224).

Almost surely, 2^21682155 is an apocalyptic number.

21682155 is a deficient number, since it is larger than the sum of its proper divisors (16373013).

21682155 is a wasteful number, since it uses less digits than its factorization.

21682155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 747.

The product of its digits is 4800, while the sum is 30.

The square root of 21682155 is about 4656.4100979188. The cubic root of 21682155 is about 278.8479663970.

The spelling of 21682155 in words is "twenty-one million, six hundred eighty-two thousand, one hundred fifty-five".