21777828281621 has 8 divisors (see below), whose sum is σ = 21900421881600. Its totient is φ = 21655417523040.

The previous prime is 21777828281617. The next prime is 21777828281681. The reversal of 21777828281621 is 12618282877712.

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 21777828281621 - 2² = 21777828281617 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21777828281611) 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, 45471461 + ... + 45947898.

It is an arithmetic number, because the mean of its divisors is an integer number (2737552735200).

Almost surely, 2^{21777828281621} is an apocalyptic number.

It is an amenable number.

21777828281621 is a deficient number, since it is larger than the sum of its proper divisors (122593599979).

21777828281621 is a wasteful number, since it uses less digits than its factorization.

21777828281621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91420699.

The product of its digits is 16859136, while the sum is 62.

The spelling of 21777828281621 in words is "twenty-one trillion, seven hundred seventy-seven billion, eight hundred twenty-eight million, two hundred eighty-one thousand, six hundred twenty-one".