21023634 has 8 divisors (see below), whose sum is σ = 42047280. Its totient is φ = 7007876.

The previous prime is 21023623. The next prime is 21023641. The reversal of 21023634 is 43632012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

21023634 is an admirable number.

It is a self number, because there is not a number n which added to its sum of digits gives 21023634.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1751964 + ... + 1751975.

It is an arithmetic number, because the mean of its divisors is an integer number (5255910).

Almost surely, 2^21023634 is an apocalyptic number.

21023634 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21023634 is a wasteful number, since it uses less digits than its factorization.

21023634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3503944.

The product of its (nonzero) digits is 864, while the sum is 21.

The square root of 21023634 is about 4585.1536506425. The cubic root of 21023634 is about 275.9958779052.

Adding to 21023634 its reverse (43632012), we get a palindrome (64655646).

The spelling of 21023634 in words is "twenty-one million, twenty-three thousand, six hundred thirty-four".