21545801027 has 4 divisors (see below), whose sum is σ = 21580609080. Its totient is φ = 21510992976.

The previous prime is 21545800999. The next prime is 21545801029. The reversal of 21545801027 is 72010854512.

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

It is a cyclic number.

It is not a de Polignac number, because 21545801027 - 2¹² = 21545796931 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21545801029) 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, 17403098 + ... + 17404335.

It is an arithmetic number, because the mean of its divisors is an integer number (5395152270).

Almost surely, 2^21545801027 is an apocalyptic number.

21545801027 is a deficient number, since it is larger than the sum of its proper divisors (34808053).

21545801027 is an equidigital number, since it uses as much as digits as its factorization.

21545801027 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34808052.

The product of its (nonzero) digits is 22400, while the sum is 35.

The spelling of 21545801027 in words is "twenty-one billion, five hundred forty-five million, eight hundred one thousand, twenty-seven".