21533058881 has 4 divisors (see below), whose sum is σ = 21535036500. Its totient is φ = 21531081264.

The previous prime is 21533058851. The next prime is 21533058931. The reversal of 21533058881 is 18885033512.

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 8156979856 + 13376079025 = 90316^2 + 115655^2 .

It is a cyclic number.

It is not a de Polignac number, because 21533058881 - 2¹⁰ = 21533057857 is a prime.

It is a super-2 number, since 2×21533058881² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21533058821) 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, 972386 + ... + 994283.

It is an arithmetic number, because the mean of its divisors is an integer number (5383759125).

Almost surely, 2^21533058881 is an apocalyptic number.

It is an amenable number.

21533058881 is a deficient number, since it is larger than the sum of its proper divisors (1977619).

21533058881 is a wasteful number, since it uses less digits than its factorization.

21533058881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1977618.

The product of its (nonzero) digits is 230400, while the sum is 44.

The spelling of 21533058881 in words is "twenty-one billion, five hundred thirty-three million, fifty-eight thousand, eight hundred eighty-one".