21461236 has 6 divisors (see below), whose sum is σ = 37557170. Its totient is φ = 10730616.

The previous prime is 21461233. The next prime is 21461249. The reversal of 21461236 is 63216412.

It can be written as a sum of positive squares in only one way, i.e., 21436900 + 24336 = 4630^2 + 156^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21461236.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21461233) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2682651 + ... + 2682658.

Almost surely, 2^21461236 is an apocalyptic number.

It is an amenable number.

21461236 is a deficient number, since it is larger than the sum of its proper divisors (16095934).

21461236 is a wasteful number, since it uses less digits than its factorization.

21461236 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5365313 (or 5365311 counting only the distinct ones).

The product of its digits is 1728, while the sum is 25.

The square root of 21461236 is about 4632.6273323029. The cubic root of 21461236 is about 277.8976729483.

Adding to 21461236 its reverse (63216412), we get a palindrome (84677648).

The spelling of 21461236 in words is "twenty-one million, four hundred sixty-one thousand, two hundred thirty-six".