1661516649 has 12 divisors (see below), whose sum is σ = 2584581636. Its totient is φ = 1022471712.

The previous prime is 1661516629. The next prime is 1661516669. The reversal of 1661516649 is 9466151661.

1661516649 is a `hidden beast` number, since 16 + 61 + 516 + 64 + 9 = 666.

It is an interprime number because it is at equal distance from previous prime (1661516629) and next prime (1661516669).

It can be written as a sum of positive squares in 2 ways, for example, as 375003225 + 1286513424 = 19365^2 + 35868^2 .

It is not a de Polignac number, because 1661516649 - 2¹² = 1661512553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1661516629) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7100382 + ... + 7100615.

It is an arithmetic number, because the mean of its divisors is an integer number (215381803).

Almost surely, 2^1661516649 is an apocalyptic number.

It is an amenable number.

1661516649 is a deficient number, since it is larger than the sum of its proper divisors (923064987).

1661516649 is a wasteful number, since it uses less digits than its factorization.

1661516649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14201016 (or 14201013 counting only the distinct ones).

The product of its digits is 233280, while the sum is 45.

The square root of 1661516649 is about 40761.7056684335. The cubic root of 1661516649 is about 1184.4086372645.

The spelling of 1661516649 in words is "one billion, six hundred sixty-one million, five hundred sixteen thousand, six hundred forty-nine".