21670136 has 8 divisors (see below), whose sum is σ = 40631520. Its totient is φ = 10835064.

The previous prime is 21670109. The next prime is 21670141. The reversal of 21670136 is 63107612.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1354376 + ... + 1354391.

It is an arithmetic number, because the mean of its divisors is an integer number (5078940).

Almost surely, 2^21670136 is an apocalyptic number.

It is an amenable number.

21670136 is a deficient number, since it is larger than the sum of its proper divisors (18961384).

21670136 is a wasteful number, since it uses less digits than its factorization.

21670136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2708773 (or 2708769 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 26.

The square root of 21670136 is about 4655.1193325198. The cubic root of 21670136 is about 278.7964325716.

Adding to 21670136 its reverse (63107612), we get a palindrome (84777748).

The spelling of 21670136 in words is "twenty-one million, six hundred seventy thousand, one hundred thirty-six".