1981761607 has 4 divisors (see below), whose sum is σ = 2264870416. Its totient is φ = 1698652800.

The previous prime is 1981761601. The next prime is 1981761619. The reversal of 1981761607 is 7061671891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7061671891 = 41257 ⋅171163.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1981761607 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1981761601) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 141554394 + ... + 141554407.

It is an arithmetic number, because the mean of its divisors is an integer number (566217604).

Almost surely, 2^1981761607 is an apocalyptic number.

1981761607 is a deficient number, since it is larger than the sum of its proper divisors (283108809).

1981761607 is an equidigital number, since it uses as much as digits as its factorization.

1981761607 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 283108808.

The product of its (nonzero) digits is 127008, while the sum is 46.

The square root of 1981761607 is about 44516.9811083366. The cubic root of 1981761607 is about 1256.0795263772.

The spelling of 1981761607 in words is "one billion, nine hundred eighty-one million, seven hundred sixty-one thousand, six hundred seven".