21634036 has 6 divisors (see below), whose sum is σ = 37859570. Its totient is φ = 10817016.

The previous prime is 21634021. The next prime is 21634037. The reversal of 21634036 is 63043612.

It can be written as a sum of positive squares in only one way, i.e., 21436900 + 197136 = 4630^2 + 444^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21634036.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21634037) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2704251 + ... + 2704258.

Almost surely, 2^21634036 is an apocalyptic number.

It is an amenable number.

21634036 is a deficient number, since it is larger than the sum of its proper divisors (16225534).

21634036 is a wasteful number, since it uses less digits than its factorization.

21634036 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5408513 (or 5408511 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 25.

The square root of 21634036 is about 4651.2402647036. The cubic root of 21634036 is about 278.6415320640.

Adding to 21634036 its reverse (63043612), we get a palindrome (84677648).

The spelling of 21634036 in words is "twenty-one million, six hundred thirty-four thousand, thirty-six".