1371721009 has 2 divisors, whose sum is σ = 1371721010. Its totient is φ = 1371721008.

The previous prime is 1371720983. The next prime is 1371721049. The reversal of 1371721009 is 9001271731.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1332031009 + 39690000 = 36497^2 + 6300^2 .

It is a cyclic number.

It is not a de Polignac number, because 1371721009 - 2¹¹ = 1371718961 is a prime.

It is not a weakly prime, because it can be changed into another prime (1371721049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 685860504 + 685860505.

It is an arithmetic number, because the mean of its divisors is an integer number (685860505).

Almost surely, 2^1371721009 is an apocalyptic number.

It is an amenable number.

1371721009 is a deficient number, since it is larger than the sum of its proper divisors (1).

1371721009 is an equidigital number, since it uses as much as digits as its factorization.

1371721009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2646, while the sum is 31.

The square root of 1371721009 is about 37036.7521389228. The cubic root of 1371721009 is about 1111.1054131415.

The spelling of 1371721009 in words is "one billion, three hundred seventy-one million, seven hundred twenty-one thousand, nine".