21550475 has 12 divisors (see below), whose sum is σ = 28295064. Its totient is φ = 16225920.

The previous prime is 21550469. The next prime is 21550493. The reversal of 21550475 is 57405512.

It is a de Polignac number, because none of the positive numbers 2^k-21550475 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 24929 + ... + 25778.

It is an arithmetic number, because the mean of its divisors is an integer number (2357922).

Almost surely, 2^21550475 is an apocalyptic number.

21550475 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21550475 is a deficient number, since it is larger than the sum of its proper divisors (6744589).

21550475 is a wasteful number, since it uses less digits than its factorization.

21550475 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50734 (or 50729 counting only the distinct ones).

The product of its (nonzero) digits is 7000, while the sum is 29.

The square root of 21550475 is about 4642.2489162043. The cubic root of 21550475 is about 278.2823202033.

Adding to 21550475 its reverse (57405512), we get a palindrome (78955987).

The spelling of 21550475 in words is "twenty-one million, five hundred fifty thousand, four hundred seventy-five".