21074881 has 4 divisors (see below), whose sum is σ = 21363652. Its totient is φ = 20786112.

The previous prime is 21074843. The next prime is 21074897. The reversal of 21074881 is 18847012.

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 8179600 + 12895281 = 2860^2 + 3591^2 .

It is a cyclic number.

It is not a de Polignac number, because 21074881 - 2¹¹ = 21072833 is a prime.

It is a super-2 number, since 2×21074881² = 888301218328322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21074681) 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, 144276 + ... + 144421.

It is an arithmetic number, because the mean of its divisors is an integer number (5340913).

Almost surely, 2^21074881 is an apocalyptic number.

It is an amenable number.

21074881 is a deficient number, since it is larger than the sum of its proper divisors (288771).

21074881 is an equidigital number, since it uses as much as digits as its factorization.

21074881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 288770.

The product of its (nonzero) digits is 3584, while the sum is 31.

The square root of 21074881 is about 4590.7386115962. The cubic root of 21074881 is about 276.2199508684.

The spelling of 21074881 in words is "twenty-one million, seventy-four thousand, eight hundred eighty-one".