1542721009 has 2 divisors, whose sum is σ = 1542721010. Its totient is φ = 1542721008.

The previous prime is 1542721003. The next prime is 1542721043. The reversal of 1542721009 is 9001272451.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1215219600 + 327501409 = 34860^2 + 18097^2 .

It is an emirp because it is prime and its reverse (9001272451) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1542721009 - 2³ = 1542721001 is a prime.

It is a super-2 number, since 2×1542721009² = 4759976223219956162, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1542721001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 771360504 + 771360505.

It is an arithmetic number, because the mean of its divisors is an integer number (771360505).

Almost surely, 2^1542721009 is an apocalyptic number.

It is an amenable number.

1542721009 is a deficient number, since it is larger than the sum of its proper divisors (1).

1542721009 is an equidigital number, since it uses as much as digits as its factorization.

1542721009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5040, while the sum is 31.

The square root of 1542721009 is about 39277.4873050708. The cubic root of 1542721009 is about 1155.4800847739.

The spelling of 1542721009 in words is "one billion, five hundred forty-two million, seven hundred twenty-one thousand, nine".