21473731 has 8 divisors (see below), whose sum is σ = 22320000. Its totient is φ = 20637120.

The previous prime is 21473719. The next prime is 21473747. The reversal of 21473731 is 13737412.

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 21473731 - 2²¹ = 19376579 is a prime.

It is a super-2 number, since 2×21473731² = 922242246120722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21473731.

It is not an unprimeable number, because it can be changed into a prime (21473531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2295 + ... + 6943.

It is an arithmetic number, because the mean of its divisors is an integer number (2790000).

Almost surely, 2^21473731 is an apocalyptic number.

21473731 is a deficient number, since it is larger than the sum of its proper divisors (846269).

21473731 is a wasteful number, since it uses less digits than its factorization.

21473731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4829.

The product of its digits is 3528, while the sum is 28.

The square root of 21473731 is about 4633.9757228540. The cubic root of 21473731 is about 277.9515943186.

The spelling of 21473731 in words is "twenty-one million, four hundred seventy-three thousand, seven hundred thirty-one".