2191971942 has 60 divisors (see below), whose sum is σ = 5217667620. Its totient is φ = 687662784.

The previous prime is 2191971941. The next prime is 2191971961. The reversal of 2191971942 is 2491791912.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2191971941) by changing a digit.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 23409 + ... + 70227.

It is an arithmetic number, because the mean of its divisors is an integer number (86961127).

Almost surely, 2^2191971942 is an apocalyptic number.

It is a pronic number, being equal to 46818×46819.

It is a practical number, because each smaller number is the sum of distinct divisors of 2191971942, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2608833810).

2191971942 is an abundant number, since it is smaller than the sum of its proper divisors (3025695678).

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

2191971942 is a wasteful number, since it uses less digits than its factorization.

2191971942 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46867 (or 46841 counting only the distinct ones).

The product of its digits is 81648, while the sum is 45.

The square root of 2191971942 is about 46818.4999973301. The cubic root of 2191971942 is about 1299.0075150641.

The spelling of 2191971942 in words is "two billion, one hundred ninety-one million, nine hundred seventy-one thousand, nine hundred forty-two".