21150155 has 16 divisors (see below), whose sum is σ = 27597024. Its totient is φ = 15467520.

The previous prime is 21150139. The next prime is 21150163. The reversal of 21150155 is 55105112.

It is a happy number.

It is not a de Polignac number, because 21150155 - 2⁴ = 21150139 is a prime.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 5435 + ... + 8475.

It is an arithmetic number, because the mean of its divisors is an integer number (1724814).

Almost surely, 2^21150155 is an apocalyptic number.

21150155 is a deficient number, since it is larger than the sum of its proper divisors (6446869).

21150155 is a wasteful number, since it uses less digits than its factorization.

21150155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3166.

The product of its (nonzero) digits is 250, while the sum is 20.

The square root of 21150155 is about 4598.9297668044. The cubic root of 21150155 is about 276.5484220759.

Adding to 21150155 its reverse (55105112), we get a palindrome (76255267).

The spelling of 21150155 in words is "twenty-one million, one hundred fifty thousand, one hundred fifty-five".