21475523 has 4 divisors (see below), whose sum is σ = 21531120. Its totient is φ = 21419928.

The previous prime is 21475511. The next prime is 21475543. The reversal of 21475523 is 32557412.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21475523 - 2⁶ = 21475459 is a prime.

It is a super-2 number, since 2×21475523² = 922396176247058, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21475543) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27215 + ... + 27992.

It is an arithmetic number, because the mean of its divisors is an integer number (5382780).

Almost surely, 2^21475523 is an apocalyptic number.

21475523 is a deficient number, since it is larger than the sum of its proper divisors (55597).

21475523 is an equidigital number, since it uses as much as digits as its factorization.

21475523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55596.

The product of its digits is 8400, while the sum is 29.

The square root of 21475523 is about 4634.1690733075. The cubic root of 21475523 is about 277.9593258644.

The spelling of 21475523 in words is "twenty-one million, four hundred seventy-five thousand, five hundred twenty-three".