21000475 has 12 divisors (see below), whose sum is σ = 26114400. Its totient is φ = 16752800.

The previous prime is 21000467. The next prime is 21000481. The reversal of 21000475 is 57400012.

It is not a de Polignac number, because 21000475 - 2³ = 21000467 is a prime.

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, 9801 + ... + 11749.

It is an arithmetic number, because the mean of its divisors is an integer number (2176200).

Almost surely, 2^21000475 is an apocalyptic number.

21000475 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21000475 is a deficient number, since it is larger than the sum of its proper divisors (5113925).

21000475 is a wasteful number, since it uses less digits than its factorization.

21000475 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2390 (or 2385 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 19.

The square root of 21000475 is about 4582.6275214117. The cubic root of 21000475 is about 275.8944977637.

Adding to 21000475 its reverse (57400012), we get a palindrome (78400487).

The spelling of 21000475 in words is "twenty-one million, four hundred seventy-five", and thus it is an aban number.