21525401 has 8 divisors (see below), whose sum is σ = 22626240. Its totient is φ = 20438352.

The previous prime is 21525373. The next prime is 21525403. The reversal of 21525401 is 10452512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21525401 - 2¹⁴ = 21509017 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21525403) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 170 + ... + 6563.

It is an arithmetic number, because the mean of its divisors is an integer number (2828280).

Almost surely, 2^21525401 is an apocalyptic number.

It is an amenable number.

21525401 is a deficient number, since it is larger than the sum of its proper divisors (1100839).

21525401 is a wasteful number, since it uses less digits than its factorization.

21525401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6895.

The product of its (nonzero) digits is 400, while the sum is 20.

The square root of 21525401 is about 4639.5474994874. The cubic root of 21525401 is about 278.1743510624.

Adding to 21525401 its reverse (10452512), we get a palindrome (31977913).

The spelling of 21525401 in words is "twenty-one million, five hundred twenty-five thousand, four hundred one".