21573198 has 12 divisors (see below), whose sum is σ = 46741968. Its totient is φ = 7191060.

The previous prime is 21573191. The next prime is 21573203. The reversal of 21573198 is 89137512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21573191) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 599238 + ... + 599273.

It is an arithmetic number, because the mean of its divisors is an integer number (3895164).

Almost surely, 2^21573198 is an apocalyptic number.

21573198 is an abundant number, since it is smaller than the sum of its proper divisors (25168770).

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

21573198 is a wasteful number, since it uses less digits than its factorization.

21573198 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1198519 (or 1198516 counting only the distinct ones).

The product of its digits is 15120, while the sum is 36.

The square root of 21573198 is about 4644.6956843264. The cubic root of 21573198 is about 278.3800935777.

The spelling of 21573198 in words is "twenty-one million, five hundred seventy-three thousand, one hundred ninety-eight".