1542745781 has 2 divisors, whose sum is σ = 1542745782. Its totient is φ = 1542745780.

The previous prime is 1542745777. The next prime is 1542745807. The reversal of 1542745781 is 1875472451.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1386370756 + 156375025 = 37234^2 + 12505^2 .

It is an emirp because it is prime and its reverse (1875472451) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1542745781 - 2² = 1542745777 is a prime.

It is a super-2 number, since 2×1542745781² = 4760129089586599922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1542745181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 771372890 + 771372891.

It is an arithmetic number, because the mean of its divisors is an integer number (771372891).

Almost surely, 2^1542745781 is an apocalyptic number.

It is an amenable number.

1542745781 is a deficient number, since it is larger than the sum of its proper divisors (1).

1542745781 is an equidigital number, since it uses as much as digits as its factorization.

1542745781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 313600, while the sum is 44.

The square root of 1542745781 is about 39277.8026498428. The cubic root of 1542745781 is about 1155.4862693873.

The spelling of 1542745781 in words is "one billion, five hundred forty-two million, seven hundred forty-five thousand, seven hundred eighty-one".