1978299720 has 256 divisors, whose sum is σ = 6995404800. Its totient is φ = 496419840.

The previous prime is 1978299647. The next prime is 1978299727. The reversal of 1978299720 is 279928791.

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

It is not an unprimeable number, because it can be changed into a prime (1978299727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1237962 + ... + 1239558.

It is an arithmetic number, because the mean of its divisors is an integer number (27325800).

Almost surely, 2^1978299720 is an apocalyptic number.

1978299720 is a gapful number since it is divisible by the number (10) 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 1978299720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3497702400).

1978299720 is an abundant number, since it is smaller than the sum of its proper divisors (5017105080).

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

1978299720 is a wasteful number, since it uses less digits than its factorization.

1978299720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1685 (or 1675 counting only the distinct ones).

The product of its (nonzero) digits is 1143072, while the sum is 54.

The square root of 1978299720 is about 44478.0813435112. The cubic root of 1978299720 is about 1255.3476960255.

The spelling of 1978299720 in words is "one billion, nine hundred seventy-eight million, two hundred ninety-nine thousand, seven hundred twenty".