21152403 has 12 divisors (see below), whose sum is σ = 32350968. Its totient is φ = 13272000.

The previous prime is 21152399. The next prime is 21152413. The reversal of 21152403 is 30425112.

21152403 is a `hidden beast` number, since 211 + 52 + 403 = 666.

It is not a de Polignac number, because 21152403 - 2² = 21152399 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21152413) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 68973 + ... + 69278.

It is an arithmetic number, because the mean of its divisors is an integer number (2695914).

Almost surely, 2^21152403 is an apocalyptic number.

21152403 is a deficient number, since it is larger than the sum of its proper divisors (11198565).

21152403 is a wasteful number, since it uses less digits than its factorization.

21152403 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138274 (or 138271 counting only the distinct ones).

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

The square root of 21152403 is about 4599.1741649996. The cubic root of 21152403 is about 276.5582196216.

Adding to 21152403 its reverse (30425112), we get a palindrome (51577515).

The spelling of 21152403 in words is "twenty-one million, one hundred fifty-two thousand, four hundred three".