1661550139 has 2 divisors, whose sum is σ = 1661550140. Its totient is φ = 1661550138.

The previous prime is 1661550109. The next prime is 1661550161. The reversal of 1661550139 is 9310551661.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1661550139 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1661550098 and 1661550107.

It is not a weakly prime, because it can be changed into another prime (1661550109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830775069 + 830775070.

It is an arithmetic number, because the mean of its divisors is an integer number (830775070).

Almost surely, 2^1661550139 is an apocalyptic number.

1661550139 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661550139 is an equidigital number, since it uses as much as digits as its factorization.

1661550139 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24300, while the sum is 37.

The square root of 1661550139 is about 40762.1164686035. The cubic root of 1661550139 is about 1184.4165949696.

The spelling of 1661550139 in words is "one billion, six hundred sixty-one million, five hundred fifty thousand, one hundred thirty-nine".