21405134 has 24 divisors (see below), whose sum is σ = 35387280. Its totient is φ = 9690912.

The previous prime is 21405127. The next prime is 21405149. The reversal of 21405134 is 43150412.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15962 + ... + 17250.

It is an arithmetic number, because the mean of its divisors is an integer number (1474470).

Almost surely, 2^21405134 is an apocalyptic number.

21405134 is a deficient number, since it is larger than the sum of its proper divisors (13982146).

21405134 is a wasteful number, since it uses less digits than its factorization.

21405134 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1352 (or 1333 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 21405134 is about 4626.5682746502. The cubic root of 21405134 is about 277.6553100791.

Adding to 21405134 its reverse (43150412), we get a palindrome (64555546).

The spelling of 21405134 in words is "twenty-one million, four hundred five thousand, one hundred thirty-four".