1940690981 has 4 divisors (see below), whose sum is σ = 2054849292. Its totient is φ = 1826532672.

The previous prime is 1940690909. The next prime is 1940691001. The reversal of 1940690981 is 1890960491.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1890960491 = 7 ⋅270137213.

It can be written as a sum of positive squares in 2 ways, for example, as 1204437025 + 736253956 = 34705^2 + 27134^2 .

It is a cyclic number.

It is not a de Polignac number, because 1940690981 - 2²² = 1936496677 is a prime.

It is a super-2 number, since 2×1940690981² = 7532562967469484722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1940690681) 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, 57079130 + ... + 57079163.

It is an arithmetic number, because the mean of its divisors is an integer number (513712323).

Almost surely, 2^1940690981 is an apocalyptic number.

It is an amenable number.

1940690981 is a deficient number, since it is larger than the sum of its proper divisors (114158311).

1940690981 is a wasteful number, since it uses less digits than its factorization.

1940690981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114158310.

The product of its (nonzero) digits is 139968, while the sum is 47.

The square root of 1940690981 is about 44053.2743504952. The cubic root of 1940690981 is about 1247.3417602965.

The spelling of 1940690981 in words is "one billion, nine hundred forty million, six hundred ninety thousand, nine hundred eighty-one".