21137471 has 8 divisors (see below), whose sum is σ = 21778560. Its totient is φ = 20500128.

The previous prime is 21137461. The next prime is 21137489. The reversal of 21137471 is 17473112.

It is a happy number.

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 21137471 - 2²² = 16943167 is a prime.

It is a super-3 number, since 3×21137471³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21137471.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21137461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13970 + ... + 15408.

It is an arithmetic number, because the mean of its divisors is an integer number (2722320).

Almost surely, 2^21137471 is an apocalyptic number.

21137471 is a deficient number, since it is larger than the sum of its proper divisors (641089).

21137471 is a wasteful number, since it uses less digits than its factorization.

21137471 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1873.

The product of its digits is 1176, while the sum is 26.

The square root of 21137471 is about 4597.5505434960. The cubic root of 21137471 is about 276.4931278928.

The spelling of 21137471 in words is "twenty-one million, one hundred thirty-seven thousand, four hundred seventy-one".