21473985 has 48 divisors (see below), whose sum is σ = 38263104. Its totient is φ = 10273536.

The previous prime is 21473953. The next prime is 21473987. The reversal of 21473985 is 58937412.

It is not a de Polignac number, because 21473985 - 2⁵ = 21473953 is a prime.

It is a super-2 number, since 2×21473985² = 922264063560450, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21473987) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 108907 + ... + 109103.

It is an arithmetic number, because the mean of its divisors is an integer number (797148).

Almost surely, 2^21473985 is an apocalyptic number.

It is an amenable number.

21473985 is a deficient number, since it is larger than the sum of its proper divisors (16789119).

21473985 is a wasteful number, since it uses less digits than its factorization.

21473985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 274 (or 261 counting only the distinct ones).

The product of its digits is 60480, while the sum is 39.

The square root of 21473985 is about 4634.0031290451. The cubic root of 21473985 is about 277.9526902224.

The spelling of 21473985 in words is "twenty-one million, four hundred seventy-three thousand, nine hundred eighty-five".