21134681 has 8 divisors (see below), whose sum is σ = 21537504. Its totient is φ = 20734560.

The previous prime is 21134657. The next prime is 21134713. The reversal of 21134681 is 18643112.

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

It is a cyclic number.

It is not a de Polignac number, because 21134681 - 2²² = 16940377 is a prime.

It is a super-2 number, since 2×21134681² = 893349481943522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21134681.

It is not an unprimeable number, because it can be changed into a prime (21134611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21701 + ... + 22653.

It is an arithmetic number, because the mean of its divisors is an integer number (2692188).

Almost surely, 2^21134681 is an apocalyptic number.

It is an amenable number.

21134681 is a deficient number, since it is larger than the sum of its proper divisors (402823).

21134681 is an equidigital number, since it uses as much as digits as its factorization.

21134681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1351.

The product of its digits is 1152, while the sum is 26.

The square root of 21134681 is about 4597.2471110437. The cubic root of 21134681 is about 276.4809622972.

Adding to 21134681 its reverse (18643112), we get a palindrome (39777793).

The spelling of 21134681 in words is "twenty-one million, one hundred thirty-four thousand, six hundred eighty-one".