1661517663 has 16 divisors (see below), whose sum is σ = 2386640256. Its totient is φ = 1022099040.

The previous prime is 1661517623. The next prime is 1661517679. The reversal of 1661517663 is 3667151661.

It is a happy number.

It is not a de Polignac number, because 1661517663 - 2¹³ = 1661509471 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661517623) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 132328 + ... + 144338.

It is an arithmetic number, because the mean of its divisors is an integer number (149165016).

Almost surely, 2^1661517663 is an apocalyptic number.

1661517663 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

1661517663 is a deficient number, since it is larger than the sum of its proper divisors (725122593).

1661517663 is a wasteful number, since it uses less digits than its factorization.

1661517663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15574.

The product of its digits is 136080, while the sum is 42.

The square root of 1661517663 is about 40761.7181065764. The cubic root of 1661517663 is about 1184.4088782070.

The spelling of 1661517663 in words is "one billion, six hundred sixty-one million, five hundred seventeen thousand, six hundred sixty-three".