2151277721 has 2 divisors, whose sum is σ = 2151277722. Its totient is φ = 2151277720.

The previous prime is 2151277649. The next prime is 2151277763. The reversal of 2151277721 is 1277721512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2012509321 + 138768400 = 44861^2 + 11780^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2151277721 is a prime.

It is not a weakly prime, because it can be changed into another prime (2151277771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1075638860 + 1075638861.

It is an arithmetic number, because the mean of its divisors is an integer number (1075638861).

Almost surely, 2^2151277721 is an apocalyptic number.

It is an amenable number.

2151277721 is a deficient number, since it is larger than the sum of its proper divisors (1).

2151277721 is an equidigital number, since it uses as much as digits as its factorization.

2151277721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13720, while the sum is 35.

The square root of 2151277721 is about 46381.8684509367. The cubic root of 2151277721 is about 1290.9185055566.

The spelling of 2151277721 in words is "two billion, one hundred fifty-one million, two hundred seventy-seven thousand, seven hundred twenty-one".