21361653 has 12 divisors (see below), whose sum is σ = 30932928. Its totient is φ = 14205480.

The previous prime is 21361619. The next prime is 21361709. The reversal of 21361653 is 35616312.

21361653 is a `hidden beast` number, since 2 + 1 + 3 + 6 + 1 + 653 = 666.

It is not a de Polignac number, because 21361653 - 2⁸ = 21361397 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21361853) 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, 1126 + ... + 6632.

It is an arithmetic number, because the mean of its divisors is an integer number (2577744).

Almost surely, 2^21361653 is an apocalyptic number.

It is an amenable number.

21361653 is a deficient number, since it is larger than the sum of its proper divisors (9571275).

21361653 is a wasteful number, since it uses less digits than its factorization.

21361653 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5944 (or 5941 counting only the distinct ones).

The product of its digits is 3240, while the sum is 27.

The square root of 21361653 is about 4621.8668306216. The cubic root of 21361653 is about 277.4671789768.

Adding to 21361653 its reverse (35616312), we get a palindrome (56977965).

The spelling of 21361653 in words is "twenty-one million, three hundred sixty-one thousand, six hundred fifty-three".