21313634 has 4 divisors (see below), whose sum is σ = 31970454. Its totient is φ = 10656816.

The previous prime is 21313609. The next prime is 21313657. The reversal of 21313634 is 43631312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 21187609 + 126025 = 4603^2 + 355^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5328407 + ... + 5328410.

Almost surely, 2^21313634 is an apocalyptic number.

21313634 is a deficient number, since it is larger than the sum of its proper divisors (10656820).

21313634 is a wasteful number, since it uses less digits than its factorization.

21313634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10656819.

The product of its digits is 1296, while the sum is 23.

The square root of 21313634 is about 4616.6691456070. The cubic root of 21313634 is about 277.2591162327.

Adding to 21313634 its reverse (43631312), we get a palindrome (64944946).

The spelling of 21313634 in words is "twenty-one million, three hundred thirteen thousand, six hundred thirty-four".