21261036 has 24 divisors (see below), whose sum is σ = 49685104. Its totient is φ = 7076160.

The previous prime is 21261029. The next prime is 21261041. The reversal of 21261036 is 63016212.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12306 + ... + 13926.

Almost surely, 2^21261036 is an apocalyptic number.

It is an amenable number.

21261036 is an abundant number, since it is smaller than the sum of its proper divisors (28424068).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21261036 is a wasteful number, since it uses less digits than its factorization.

21261036 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2721 (or 2719 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 21261036 is about 4610.9690955373. The cubic root of 21261036 is about 277.0308540833.

Adding to 21261036 its reverse (63016212), we get a palindrome (84277248).

The spelling of 21261036 in words is "twenty-one million, two hundred sixty-one thousand, thirty-six".