21131473 has 8 divisors (see below), whose sum is σ = 23345280. Its totient is φ = 18966480.

The previous prime is 21131449. The next prime is 21131489. The reversal of 21131473 is 37413112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21131473 - 2⁹ = 21130961 is a prime.

It is a super-2 number, since 2×21131473² = 893078302299458, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21131423) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11290 + ... + 13027.

It is an arithmetic number, because the mean of its divisors is an integer number (2918160).

Almost surely, 2^21131473 is an apocalyptic number.

It is an amenable number.

21131473 is a deficient number, since it is larger than the sum of its proper divisors (2213807).

21131473 is a wasteful number, since it uses less digits than its factorization.

21131473 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24407.

The product of its digits is 504, while the sum is 22.

The square root of 21131473 is about 4596.8981933473. The cubic root of 21131473 is about 276.4669727192.

Adding to 21131473 its reverse (37413112), we get a palindrome (58544585).

It can be divided in two parts, 211 and 31473, that added together give a square (31684 = 178²).

The spelling of 21131473 in words is "twenty-one million, one hundred thirty-one thousand, four hundred seventy-three".