1978797600 has 648 divisors, whose sum is σ = 8072178660. Its totient is φ = 470292480.

The previous prime is 1978797553. The next prime is 1978797647. The reversal of 1978797600 is 67978791.

It is an interprime number because it is at equal distance from previous prime (1978797553) and next prime (1978797647).

It can be written as a sum of positive squares in 6 ways, for example, as 390615696 + 1588181904 = 19764^2 + 39852^2 .

It is a tau number, because it is divible by the number of its divisors (648).

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

It is an unprimeable number.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 68234386 + ... + 68234414.

Almost surely, 2^1978797600 is an apocalyptic number.

1978797600 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 1978797600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4036089330).

1978797600 is an abundant number, since it is smaller than the sum of its proper divisors (6093381060).

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

1978797600 is an equidigital number, since it uses as much as digits as its factorization.

1978797600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86 (or 52 counting only the distinct ones).

The product of its (nonzero) digits is 1333584, while the sum is 54.

The square root of 1978797600 is about 44483.6779054970. The cubic root of 1978797600 is about 1255.4529985873.

The spelling of 1978797600 in words is "one billion, nine hundred seventy-eight million, seven hundred ninety-seven thousand, six hundred".