1978780650 has 384 divisors, whose sum is σ = 6582435840. Its totient is φ = 381024000.

The previous prime is 1978780619. The next prime is 1978780681. The reversal of 1978780650 is 560878791.

It is an interprime number because it is at equal distance from previous prime (1978780619) and next prime (1978780681).

It is a junction number, because it is equal to n+sod(n) for n = 1978780593 and 1978780602.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 15580887 + ... + 15581013.

It is an arithmetic number, because the mean of its divisors is an integer number (17141760).

Almost surely, 2^1978780650 is an apocalyptic number.

1978780650 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1978780650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3291217920).

1978780650 is an abundant number, since it is smaller than the sum of its proper divisors (4603655190).

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

1978780650 is a wasteful number, since it uses less digits than its factorization.

1978780650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 250 (or 245 counting only the distinct ones).

The product of its (nonzero) digits is 846720, while the sum is 51.

The square root of 1978780650 is about 44483.4873857705. The cubic root of 1978780650 is about 1255.4494139207.

The spelling of 1978780650 in words is "one billion, nine hundred seventy-eight million, seven hundred eighty thousand, six hundred fifty".