21445627721 has 8 divisors (see below), whose sum is σ = 25951011840. Its totient is φ = 17300674368.

The previous prime is 21445627699. The next prime is 21445627741. The reversal of 21445627721 is 12772654412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21445627721 - 2⁶ = 21445627657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21445627741) 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, 90107561 + ... + 90107798.

It is an arithmetic number, because the mean of its divisors is an integer number (3243876480).

Almost surely, 2^21445627721 is an apocalyptic number.

It is an amenable number.

21445627721 is a deficient number, since it is larger than the sum of its proper divisors (4505384119).

21445627721 is a wasteful number, since it uses less digits than its factorization.

21445627721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180215383.

The product of its digits is 188160, while the sum is 41.

The spelling of 21445627721 in words is "twenty-one billion, four hundred forty-five million, six hundred twenty-seven thousand, seven hundred twenty-one".