21698161 has 8 divisors (see below), whose sum is σ = 22227840. Its totient is φ = 21171408.

The previous prime is 21698153. The next prime is 21698167. The reversal of 21698161 is 16189612.

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 21698161 - 2³ = 21698153 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21698167) 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, 23470 + ... + 24376.

It is an arithmetic number, because the mean of its divisors is an integer number (2778480).

Almost surely, 2^21698161 is an apocalyptic number.

It is an amenable number.

21698161 is a deficient number, since it is larger than the sum of its proper divisors (529679).

21698161 is an equidigital number, since it uses as much as digits as its factorization.

21698161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1463.

The product of its digits is 5184, while the sum is 34.

The square root of 21698161 is about 4658.1284868496. The cubic root of 21698161 is about 278.9165657087.

The spelling of 21698161 in words is "twenty-one million, six hundred ninety-eight thousand, one hundred sixty-one".