21261203 has 8 divisors (see below), whose sum is σ = 22559472. Its totient is φ = 19968256.

The previous prime is 21261193. The next prime is 21261211. The reversal of 21261203 is 30216212.

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

It is a cyclic number.

It is not a de Polignac number, because 21261203 - 2⁴ = 21261187 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21261283) 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, 9476 + ... + 11502.

It is an arithmetic number, because the mean of its divisors is an integer number (2819934).

Almost surely, 2^21261203 is an apocalyptic number.

21261203 is a deficient number, since it is larger than the sum of its proper divisors (1298269).

21261203 is a wasteful number, since it uses less digits than its factorization.

21261203 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2661.

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 21261203 is about 4610.9872044932. The cubic root of 21261203 is about 277.0315794169.

Adding to 21261203 its reverse (30216212), we get a palindrome (51477415).

The spelling of 21261203 in words is "twenty-one million, two hundred sixty-one thousand, two hundred three".