21700998 has 48 divisors (see below), whose sum is σ = 51757056. Its totient is φ = 6516720.

The previous prime is 21700979. The next prime is 21700999. The reversal of 21700998 is 89900712.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21700999) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 24715 + ... + 25577.

It is an arithmetic number, because the mean of its divisors is an integer number (1078272).

Almost surely, 2^21700998 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21700998, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25878528).

21700998 is an abundant number, since it is smaller than the sum of its proper divisors (30056058).

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

21700998 is a wasteful number, since it uses less digits than its factorization.

21700998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1009 (or 1006 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 36.

The square root of 21700998 is about 4658.4329983375. The cubic root of 21700998 is about 278.9287211445.

The spelling of 21700998 in words is "twenty-one million, seven hundred thousand, nine hundred ninety-eight".