21617898 has 8 divisors (see below), whose sum is σ = 43235808. Its totient is φ = 7205964.

The previous prime is 21617873. The next prime is 21617899. The reversal of 21617898 is 89871612.

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

21617898 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (21617899) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1801486 + ... + 1801497.

It is an arithmetic number, because the mean of its divisors is an integer number (5404476).

Almost surely, 2^21617898 is an apocalyptic number.

21617898 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21617898 is a wasteful number, since it uses less digits than its factorization.

21617898 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3602988.

The product of its digits is 48384, while the sum is 42.

The square root of 21617898 is about 4649.5051349579. The cubic root of 21617898 is about 278.5722302222.

The spelling of 21617898 in words is "twenty-one million, six hundred seventeen thousand, eight hundred ninety-eight".