21125874 has 48 divisors (see below), whose sum is σ = 53089344. Its totient is φ = 5485920.

The previous prime is 21125869. The next prime is 21125879. The reversal of 21125874 is 47852112.

It is an interprime number because it is at equal distance from previous prime (21125869) and next prime (21125879).

It is not an unprimeable number, because it can be changed into a prime (21125879) 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, 3004 + ... + 7160.

It is an arithmetic number, because the mean of its divisors is an integer number (1106028).

Almost surely, 2^21125874 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21125874, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26544672).

21125874 is an abundant number, since it is smaller than the sum of its proper divisors (31963470).

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

21125874 is a wasteful number, since it uses less digits than its factorization.

21125874 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4191 (or 4180 counting only the distinct ones).

The product of its digits is 4480, while the sum is 30.

The square root of 21125874 is about 4596.2891553948. The cubic root of 21125874 is about 276.4425529779.

Adding to 21125874 its reverse (47852112), we get a palindrome (68977986).

The spelling of 21125874 in words is "twenty-one million, one hundred twenty-five thousand, eight hundred seventy-four".