1980663761 has 16 divisors (see below), whose sum is σ = 2178115920. Its totient is φ = 1793341440.

The previous prime is 1980663733. The next prime is 1980663767. The reversal of 1980663761 is 1673660891.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 329785600 + 1650878161 = 18160^2 + 40631^2 .

It is a cyclic number.

It is not a de Polignac number, because 1980663761 - 2¹⁴ = 1980647377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1980663767) 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, 38291 + ... + 73671.

It is an arithmetic number, because the mean of its divisors is an integer number (136132245).

Almost surely, 2^1980663761 is an apocalyptic number.

It is an amenable number.

1980663761 is a deficient number, since it is larger than the sum of its proper divisors (197452159).

1980663761 is a wasteful number, since it uses less digits than its factorization.

1980663761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35524.

The product of its (nonzero) digits is 326592, while the sum is 47.

The square root of 1980663761 is about 44504.6487571804. The cubic root of 1980663761 is about 1255.8475380631.

The spelling of 1980663761 in words is "one billion, nine hundred eighty million, six hundred sixty-three thousand, seven hundred sixty-one".