21698371 has 8 divisors (see below), whose sum is σ = 22431600. Its totient is φ = 20977440.

The previous prime is 21698321. The next prime is 21698387. The reversal of 21698371 is 17389612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21698371 is a prime.

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 21698371.

It is not an unprimeable number, because it can be changed into a prime (21698311) 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, 585 + ... + 6613.

It is an arithmetic number, because the mean of its divisors is an integer number (2803950).

Almost surely, 2^21698371 is an apocalyptic number.

21698371 is a deficient number, since it is larger than the sum of its proper divisors (733229).

21698371 is an equidigital number, since it uses as much as digits as its factorization.

21698371 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6149.

The product of its digits is 18144, while the sum is 37.

The square root of 21698371 is about 4658.1510280368. The cubic root of 21698371 is about 278.9174655129.

The spelling of 21698371 in words is "twenty-one million, six hundred ninety-eight thousand, three hundred seventy-one".