2171854721 has 2 divisors, whose sum is σ = 2171854722. Its totient is φ = 2171854720.

The previous prime is 2171854693. The next prime is 2171854759. The reversal of 2171854721 is 1274581712.

2171854721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an a-pointer prime, because the next prime (2171854759) can be obtained adding 2171854721 to its sum of digits (38).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2161227121 + 10627600 = 46489^2 + 3260^2 .

It is a cyclic number.

It is not a de Polignac number, because 2171854721 - 2¹⁴ = 2171838337 is a prime.

It is not a weakly prime, because it can be changed into another prime (2171854021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1085927360 + 1085927361.

It is an arithmetic number, because the mean of its divisors is an integer number (1085927361).

Almost surely, 2^2171854721 is an apocalyptic number.

It is an amenable number.

2171854721 is a deficient number, since it is larger than the sum of its proper divisors (1).

2171854721 is an equidigital number, since it uses as much as digits as its factorization.

2171854721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 31360, while the sum is 38.

The square root of 2171854721 is about 46603.1621352028. The cubic root of 2171854721 is about 1295.0213362415.

The spelling of 2171854721 in words is "two billion, one hundred seventy-one million, eight hundred fifty-four thousand, seven hundred twenty-one".