21771700221 has 16 divisors (see below), whose sum is σ = 30837118400. Its totient is φ = 13624391808.

The previous prime is 21771700193. The next prime is 21771700229. The reversal of 21771700221 is 12200717712.

It is not a de Polignac number, because 21771700221 - 2⁹ = 21771699709 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 (21771700229) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1745896 + ... + 1758321.

It is an arithmetic number, because the mean of its divisors is an integer number (1927319900).

Almost surely, 2^21771700221 is an apocalyptic number.

It is an amenable number.

21771700221 is a deficient number, since it is larger than the sum of its proper divisors (9065418179).

21771700221 is a wasteful number, since it uses less digits than its factorization.

21771700221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3504348.

The product of its (nonzero) digits is 2744, while the sum is 30.

The spelling of 21771700221 in words is "twenty-one billion, seven hundred seventy-one million, seven hundred thousand, two hundred twenty-one".