21525378 has 32 divisors (see below), whose sum is σ = 51342336. Its totient is φ = 5882448.

The previous prime is 21525373. The next prime is 21525403. The reversal of 21525378 is 87352512.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21525373) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10176 + ... + 12107.

It is an arithmetic number, because the mean of its divisors is an integer number (1604448).

Almost surely, 2^21525378 is an apocalyptic number.

21525378 is an abundant number, since it is smaller than the sum of its proper divisors (29816958).

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

21525378 is a wasteful number, since it uses less digits than its factorization.

21525378 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22318.

The product of its digits is 16800, while the sum is 33.

The square root of 21525378 is about 4639.5450207968. The cubic root of 21525378 is about 278.1742519855.

The spelling of 21525378 in words is "twenty-one million, five hundred twenty-five thousand, three hundred seventy-eight".