21336261 has 12 divisors (see below), whose sum is σ = 29128512. Its totient is φ = 13885744.

The previous prime is 21336253. The next prime is 21336283. The reversal of 21336261 is 16263312.

It is a happy number.

It is not a de Polignac number, because 21336261 - 2³ = 21336253 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21336251) 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, 54655 + ... + 55043.

It is an arithmetic number, because the mean of its divisors is an integer number (2427376).

Almost surely, 2^21336261 is an apocalyptic number.

It is an amenable number.

21336261 is a deficient number, since it is larger than the sum of its proper divisors (7792251).

21336261 is an frugal number, since it uses more digits than its factorization.

21336261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 828 (or 439 counting only the distinct ones).

The product of its digits is 1296, while the sum is 24.

The square root of 21336261 is about 4619.1190718577. The cubic root of 21336261 is about 277.3571962267.

Adding to 21336261 its reverse (16263312), we get a palindrome (37599573).

The spelling of 21336261 in words is "twenty-one million, three hundred thirty-six thousand, two hundred sixty-one".