21253401 has 32 divisors (see below), whose sum is σ = 34218240. Its totient is φ = 12960000.

The previous prime is 21253373. The next prime is 21253423. The reversal of 21253401 is 10435212.

21253401 is a `hidden beast` number, since 212 + 53 + 401 = 666.

It is not a de Polignac number, because 21253401 - 2¹⁰ = 21252377 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21253471) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 52801 + ... + 53201.

It is an arithmetic number, because the mean of its divisors is an integer number (1069320).

Almost surely, 2^21253401 is an apocalyptic number.

It is an amenable number.

21253401 is a deficient number, since it is larger than the sum of its proper divisors (12964839).

21253401 is a wasteful number, since it uses less digits than its factorization.

21253401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 574 (or 568 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 21253401 is about 4610.1411041312. The cubic root of 21253401 is about 276.9976888163.

Adding to 21253401 its reverse (10435212), we get a palindrome (31688613).

The spelling of 21253401 in words is "twenty-one million, two hundred fifty-three thousand, four hundred one".