21581048066 has 16 divisors (see below), whose sum is σ = 33471053280. Its totient is φ = 10428949920.

The previous prime is 21581048063. The next prime is 21581048113. The reversal of 21581048066 is 66084018512.

It is a Harshad number since it is a multiple of its sum of digits (41).

It is not an unprimeable number, because it can be changed into a prime (21581048063) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1221056 + ... + 1238603.

It is an arithmetic number, because the mean of its divisors is an integer number (2091940830).

Almost surely, 2^21581048066 is an apocalyptic number.

21581048066 is a deficient number, since it is larger than the sum of its proper divisors (11890005214).

21581048066 is a wasteful number, since it uses less digits than its factorization.

21581048066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2459809.

The product of its (nonzero) digits is 92160, while the sum is 41.

The spelling of 21581048066 in words is "twenty-one billion, five hundred eighty-one million, forty-eight thousand, sixty-six".