2142678721 has 2 divisors, whose sum is σ = 2142678722. Its totient is φ = 2142678720.

The previous prime is 2142678719. The next prime is 2142678743. The reversal of 2142678721 is 1278762412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1811438721 + 331240000 = 42561^2 + 18200^2 .

It is a cyclic number.

It is not a de Polignac number, because 2142678721 - 2¹ = 2142678719 is a prime.

Together with 2142678719, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (2142678761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1071339360 + 1071339361.

It is an arithmetic number, because the mean of its divisors is an integer number (1071339361).

Almost surely, 2^2142678721 is an apocalyptic number.

It is an amenable number.

2142678721 is a deficient number, since it is larger than the sum of its proper divisors (1).

2142678721 is an equidigital number, since it uses as much as digits as its factorization.

2142678721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 75264, while the sum is 40.

The square root of 2142678721 is about 46289.0777721916. The cubic root of 2142678721 is about 1289.1962063926.

The spelling of 2142678721 in words is "two billion, one hundred forty-two million, six hundred seventy-eight thousand, seven hundred twenty-one".