21152401 has 4 divisors (see below), whose sum is σ = 21176100. Its totient is φ = 21128704.

The previous prime is 21152399. The next prime is 21152413. The reversal of 21152401 is 10425112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 358801 + 20793600 = 599^2 + 4560^2 .

It is a cyclic number.

It is not a de Polignac number, because 21152401 - 2¹ = 21152399 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21152441) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10456 + ... + 12313.

It is an arithmetic number, because the mean of its divisors is an integer number (5294025).

Almost surely, 2^21152401 is an apocalyptic number.

It is an amenable number.

21152401 is a deficient number, since it is larger than the sum of its proper divisors (23699).

21152401 is an equidigital number, since it uses as much as digits as its factorization.

21152401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23698.

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 21152401 is about 4599.1739475693. The cubic root of 21152401 is about 276.5582109052.

Adding to 21152401 its reverse (10425112), we get a palindrome (31577513).

The spelling of 21152401 in words is "twenty-one million, one hundred fifty-two thousand, four hundred one".