21275898 has 24 divisors (see below), whose sum is σ = 49499712. Its totient is φ = 6078744.

The previous prime is 21275893. The next prime is 21275909. The reversal of 21275898 is 89857212.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21275893) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 35890 + ... + 36477.

It is an arithmetic number, because the mean of its divisors is an integer number (2062488).

Almost surely, 2^21275898 is an apocalyptic number.

21275898 is an abundant number, since it is smaller than the sum of its proper divisors (28223814).

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

21275898 is a wasteful number, since it uses less digits than its factorization.

21275898 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72386 (or 72379 counting only the distinct ones).

The product of its digits is 80640, while the sum is 42.

The square root of 21275898 is about 4612.5804058032. The cubic root of 21275898 is about 277.0953895647.

The spelling of 21275898 in words is "twenty-one million, two hundred seventy-five thousand, eight hundred ninety-eight".