21014881 has 4 divisors (see below), whose sum is σ = 21081492. Its totient is φ = 20948272.

The previous prime is 21014867. The next prime is 21014887. The reversal of 21014881 is 18841012.

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

It can be written as a sum of positive squares in 2 ways, for example, as 2387025 + 18627856 = 1545^2 + 4316^2 .

It is a cyclic number.

It is not a de Polignac number, because 21014881 - 2⁵ = 21014849 is a prime.

It is a super-2 number, since 2×21014881² = 883250446888322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21014887) 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, 32830 + ... + 33463.

It is an arithmetic number, because the mean of its divisors is an integer number (5270373).

Almost surely, 2^21014881 is an apocalyptic number.

It is an amenable number.

21014881 is a deficient number, since it is larger than the sum of its proper divisors (66611).

21014881 is an equidigital number, since it uses as much as digits as its factorization.

21014881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66610.

The product of its (nonzero) digits is 512, while the sum is 25.

The square root of 21014881 is about 4584.1990576326. The cubic root of 21014881 is about 275.9575697919.

Adding to 21014881 its reverse (18841012), we get a palindrome (39855893).

The spelling of 21014881 in words is "twenty-one million, fourteen thousand, eight hundred eighty-one".