1961719128 has 128 divisors (see below), whose sum is σ = 5825433600. Its totient is φ = 610156800.

The previous prime is 1961719127. The next prime is 1961719147. The reversal of 1961719128 is 8219171691.

It is a happy number.

1961719128 is a `hidden beast` number, since 1 + 9 + 617 + 1 + 9 + 1 + 28 = 666.

It is a super-2 number, since 2×1961719128² = 7696683874322160768, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1961719121) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 198873 + ... + 208503.

It is an arithmetic number, because the mean of its divisors is an integer number (45511200).

Almost surely, 2^1961719128 is an apocalyptic number.

1961719128 is a gapful number since it is divisible by the number (18) 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 1961719128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2912716800).

1961719128 is an abundant number, since it is smaller than the sum of its proper divisors (3863714472).

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

1961719128 is a wasteful number, since it uses less digits than its factorization.

1961719128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9710 (or 9700 counting only the distinct ones).

The product of its digits is 54432, while the sum is 45.

The square root of 1961719128 is about 44291.2985585205. The cubic root of 1961719128 is about 1251.8307314024.

The spelling of 1961719128 in words is "one billion, nine hundred sixty-one million, seven hundred nineteen thousand, one hundred twenty-eight".