1978540992 has 98 divisors (see below), whose sum is σ = 5886696888. Its totient is φ = 659498112.

The previous prime is 1978540939. The next prime is 1978541011. The reversal of 1978540992 is 2990458791.

1978540992 is a `hidden beast` number, since 1 + 9 + 7 + 8 + 540 + 9 + 92 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 25453 + ... + 67859.

Almost surely, 2^1978540992 is an apocalyptic number.

1978540992 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1978540992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2943348444).

1978540992 is an abundant number, since it is smaller than the sum of its proper divisors (3908155896).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1978540992 is an frugal number, since it uses more digits than its factorization.

1978540992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42437 (or 42412 counting only the distinct ones).

The product of its (nonzero) digits is 1632960, while the sum is 54.

The square root of 1978540992 is about 44480.7935181017. The cubic root of 1978540992 is about 1255.3987277160.

The spelling of 1978540992 in words is "one billion, nine hundred seventy-eight million, five hundred forty thousand, nine hundred ninety-two".