1951220778 has 64 divisors (see below), whose sum is σ = 4408411392. Its totient is φ = 571253760.

The previous prime is 1951220771. The next prime is 1951220779. The reversal of 1951220778 is 8770221591.

It is not an unprimeable number, because it can be changed into a prime (1951220771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 350658 + ... + 356178.

It is an arithmetic number, because the mean of its divisors is an integer number (68881428).

Almost surely, 2^1951220778 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1951220778, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2204205696).

1951220778 is an abundant number, since it is smaller than the sum of its proper divisors (2457190614).

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

1951220778 is a wasteful number, since it uses less digits than its factorization.

1951220778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5759.

The product of its (nonzero) digits is 70560, while the sum is 42.

The square root of 1951220778 is about 44172.6247578746. The cubic root of 1951220778 is about 1249.5936338809.

The spelling of 1951220778 in words is "one billion, nine hundred fifty-one million, two hundred twenty thousand, seven hundred seventy-eight".