21351634 has 8 divisors (see below), whose sum is σ = 32387580. Its totient is φ = 10555776.

The previous prime is 21351619. The next prime is 21351637. The reversal of 21351634 is 43615312.

It can be written as a sum of positive squares in 2 ways, for example, as 21187609 + 164025 = 4603^2 + 405^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 21351599 and 21351608.

It is not an unprimeable number, because it can be changed into a prime (21351637) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 59799 + ... + 60154.

Almost surely, 2^21351634 is an apocalyptic number.

21351634 is a deficient number, since it is larger than the sum of its proper divisors (11035946).

21351634 is a wasteful number, since it uses less digits than its factorization.

21351634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120044.

The product of its digits is 2160, while the sum is 25.

The square root of 21351634 is about 4620.7828341094. The cubic root of 21351634 is about 277.4237931584.

Adding to 21351634 its reverse (43615312), we get a palindrome (64966946).

The spelling of 21351634 in words is "twenty-one million, three hundred fifty-one thousand, six hundred thirty-four".