1992978949 has 4 divisors (see below), whose sum is σ = 2146285036. Its totient is φ = 1839672864.

The previous prime is 1992978937. The next prime is 1992978979. The reversal of 1992978949 is 9498792991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9498792991 = 3467 ⋅2739773.

It can be written as a sum of positive squares in 2 ways, for example, as 585978849 + 1407000100 = 24207^2 + 37510^2 .

It is a cyclic number.

It is not a de Polignac number, because 1992978949 - 2⁵ = 1992978917 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 (1992978979) 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, 76653024 + ... + 76653049.

It is an arithmetic number, because the mean of its divisors is an integer number (536571259).

Almost surely, 2^1992978949 is an apocalyptic number.

It is an amenable number.

1992978949 is a deficient number, since it is larger than the sum of its proper divisors (153306087).

1992978949 is a wasteful number, since it uses less digits than its factorization.

1992978949 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 153306086.

The product of its digits is 26453952, while the sum is 67.

The square root of 1992978949 is about 44642.7928001822. The cubic root of 1992978949 is about 1258.4449929754. Note that the first 3 decimals are identical.

The spelling of 1992978949 in words is "one billion, nine hundred ninety-two million, nine hundred seventy-eight thousand, nine hundred forty-nine".