21575055 has 16 divisors (see below), whose sum is σ = 34644960. Its totient is φ = 11465088.

The previous prime is 21575053. The next prime is 21575069. The reversal of 21575055 is 55057512.

It is not a de Polignac number, because 21575055 - 2¹ = 21575053 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21575053) by changing a digit.

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, 1941 + ... + 6849.

It is an arithmetic number, because the mean of its divisors is an integer number (2165310).

Almost surely, 2^21575055 is an apocalyptic number.

21575055 is a deficient number, since it is larger than the sum of its proper divisors (13069905).

21575055 is a wasteful number, since it uses less digits than its factorization.

21575055 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5210.

The product of its (nonzero) digits is 8750, while the sum is 30.

The square root of 21575055 is about 4644.8955854788. The cubic root of 21575055 is about 278.3880809115.

It can be divided in two parts, 21 and 575055, that multiplied together give a triangular number (12076155 = T₄₉₁₄).

The spelling of 21575055 in words is "twenty-one million, five hundred seventy-five thousand, fifty-five".