21156473 has 8 divisors (see below), whose sum is σ = 23314368. Its totient is φ = 19074384.

The previous prime is 21156463. The next prime is 21156493. The reversal of 21156473 is 37465112.

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 21156473 - 2¹⁴ = 21140089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21156403) 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, 18365 + ... + 19482.

It is an arithmetic number, because the mean of its divisors is an integer number (2914296).

Almost surely, 2^21156473 is an apocalyptic number.

It is an amenable number.

21156473 is a deficient number, since it is larger than the sum of its proper divisors (2157895).

21156473 is a wasteful number, since it uses less digits than its factorization.

21156473 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37903.

The product of its digits is 5040, while the sum is 29.

The square root of 21156473 is about 4599.6166144582. The cubic root of 21156473 is about 276.5759562946.

The spelling of 21156473 in words is "twenty-one million, one hundred fifty-six thousand, four hundred seventy-three".