21698534 has 16 divisors (see below), whose sum is σ = 38238480. Its totient is φ = 9104160.

The previous prime is 21698533. The next prime is 21698561. The reversal of 21698534 is 43589612.

It is a happy number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21698533) 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, 37649 + ... + 38220.

It is an arithmetic number, because the mean of its divisors is an integer number (2389905).

Almost surely, 2^21698534 is an apocalyptic number.

21698534 is a deficient number, since it is larger than the sum of its proper divisors (16539946).

21698534 is a wasteful number, since it uses less digits than its factorization.

21698534 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75895.

The product of its digits is 51840, while the sum is 38.

The square root of 21698534 is about 4658.1685242164. The cubic root of 21698534 is about 278.9181639283.

The spelling of 21698534 in words is "twenty-one million, six hundred ninety-eight thousand, five hundred thirty-four".