21813698 has 4 divisors (see below), whose sum is σ = 32720550. Its totient is φ = 10906848.

The previous prime is 21813697. The next prime is 21813709. The reversal of 21813698 is 89631812.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 20675209 + 1138489 = 4547^2 + 1067^2 .

It is not an unprimeable number, because it can be changed into a prime (21813697) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5453423 + ... + 5453426.

Almost surely, 2^21813698 is an apocalyptic number.

21813698 is a deficient number, since it is larger than the sum of its proper divisors (10906852).

21813698 is a wasteful number, since it uses less digits than its factorization.

21813698 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10906851.

The product of its digits is 20736, while the sum is 38.

The square root of 21813698 is about 4670.5136762459. The cubic root of 21813698 is about 279.4107420735.

The spelling of 21813698 in words is "twenty-one million, eight hundred thirteen thousand, six hundred ninety-eight".