1661504617 has 2 divisors, whose sum is σ = 1661504618. Its totient is φ = 1661504616.

The previous prime is 1661504591. The next prime is 1661504651. The reversal of 1661504617 is 7164051661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1424005696 + 237498921 = 37736^2 + 15411^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1661504617 is a prime.

It is not a weakly prime, because it can be changed into another prime (1661504687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830752308 + 830752309.

It is an arithmetic number, because the mean of its divisors is an integer number (830752309).

Almost surely, 2^1661504617 is an apocalyptic number.

It is an amenable number.

1661504617 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661504617 is an equidigital number, since it uses as much as digits as its factorization.

1661504617 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 30240, while the sum is 37.

The square root of 1661504617 is about 40761.5580786603. The cubic root of 1661504617 is about 1184.4057782623.

The spelling of 1661504617 in words is "one billion, six hundred sixty-one million, five hundred four thousand, six hundred seventeen".