21965598 has 48 divisors (see below), whose sum is σ = 52599456. Its totient is φ = 6589440.

The previous prime is 21965569. The next prime is 21965599. The reversal of 21965598 is 89556912.

21965598 is a `hidden beast` number, since 2 + 1 + 96 + 559 + 8 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21965599) 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, 5478 + ... + 8598.

It is an arithmetic number, because the mean of its divisors is an integer number (1095822).

Almost surely, 2^21965598 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21965598, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26299728).

21965598 is an abundant number, since it is smaller than the sum of its proper divisors (30633858).

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

21965598 is a wasteful number, since it uses less digits than its factorization.

21965598 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3169 (or 3166 counting only the distinct ones).

The product of its digits is 194400, while the sum is 45.

The square root of 21965598 is about 4686.7470595286. The cubic root of 21965598 is about 280.0578026923.

The spelling of 21965598 in words is "twenty-one million, nine hundred sixty-five thousand, five hundred ninety-eight".