21246155 has 12 divisors (see below), whose sum is σ = 29658240. Its totient is φ = 14568624.

The previous prime is 21246151. The next prime is 21246167. The reversal of 21246155 is 55164212.

It is not a de Polignac number, because 21246155 - 2² = 21246151 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21246151) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 43115 + ... + 43604.

It is an arithmetic number, because the mean of its divisors is an integer number (2471520).

Almost surely, 2^21246155 is an apocalyptic number.

21246155 is a deficient number, since it is larger than the sum of its proper divisors (8412085).

21246155 is an equidigital number, since it uses as much as digits as its factorization.

21246155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86738 (or 86731 counting only the distinct ones).

The product of its digits is 2400, while the sum is 26.

The square root of 21246155 is about 4609.3551609743. The cubic root of 21246155 is about 276.9662059587.

The spelling of 21246155 in words is "twenty-one million, two hundred forty-six thousand, one hundred fifty-five".