21478055 has 16 divisors (see below), whose sum is σ = 27959904. Its totient is φ = 15774720.

The previous prime is 21478049. The next prime is 21478057. The reversal of 21478055 is 55087412.

It is not a de Polignac number, because 21478055 - 2⁶ = 21477991 is a prime.

It is a super-2 number, since 2×21478055² = 922613693166050, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21478057) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 404 + ... + 6566.

It is an arithmetic number, because the mean of its divisors is an integer number (1747494).

Almost surely, 2^21478055 is an apocalyptic number.

21478055 is a deficient number, since it is larger than the sum of its proper divisors (6481849).

21478055 is a wasteful number, since it uses less digits than its factorization.

21478055 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6226.

The product of its (nonzero) digits is 11200, while the sum is 32.

The square root of 21478055 is about 4634.4422533893. The cubic root of 21478055 is about 277.9702493912.

The spelling of 21478055 in words is "twenty-one million, four hundred seventy-eight thousand, fifty-five".