21525234 has 16 divisors (see below), whose sum is σ = 43176672. Its totient is φ = 7154048.

The previous prime is 21525227. The next prime is 21525277. The reversal of 21525234 is 43252512.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2964 + ... + 7199.

It is an arithmetic number, because the mean of its divisors is an integer number (2698542).

Almost surely, 2^21525234 is an apocalyptic number.

21525234 is an abundant number, since it is smaller than the sum of its proper divisors (21651438).

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

21525234 is a wasteful number, since it uses less digits than its factorization.

21525234 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10521.

The product of its digits is 2400, while the sum is 24.

The square root of 21525234 is about 4639.5295020077. The cubic root of 21525234 is about 278.1736316761.

Adding to 21525234 its reverse (43252512), we get a palindrome (64777746).

The spelling of 21525234 in words is "twenty-one million, five hundred twenty-five thousand, two hundred thirty-four".