21497161 has 8 divisors (see below), whose sum is σ = 25167744. Its totient is φ = 17976480.

The previous prime is 21497141. The next prime is 21497183. The reversal of 21497161 is 16179412.

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 21497161 - 2⁹ = 21496649 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21497101) 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, 37165 + ... + 37738.

It is an arithmetic number, because the mean of its divisors is an integer number (3145968).

Almost surely, 2^21497161 is an apocalyptic number.

It is an amenable number.

21497161 is a deficient number, since it is larger than the sum of its proper divisors (3670583).

21497161 is an equidigital number, since it uses as much as digits as its factorization.

21497161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74951.

The product of its digits is 3024, while the sum is 31.

The square root of 21497161 is about 4636.5031003980. The cubic root of 21497161 is about 278.0526486211.

The spelling of 21497161 in words is "twenty-one million, four hundred ninety-seven thousand, one hundred sixty-one".