2123781499 has 4 divisors (see below), whose sum is σ = 2427178864. Its totient is φ = 1820384136.

The previous prime is 2123781461. The next prime is 2123781557. The reversal of 2123781499 is 9941873212.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 2123781499 - 2⁷ = 2123781371 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2123781299) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 151698672 + ... + 151698685.

It is an arithmetic number, because the mean of its divisors is an integer number (606794716).

Almost surely, 2^2123781499 is an apocalyptic number.

2123781499 is a deficient number, since it is larger than the sum of its proper divisors (303397365).

2123781499 is an equidigital number, since it uses as much as digits as its factorization.

2123781499 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 303397364.

The product of its digits is 217728, while the sum is 46.

The square root of 2123781499 is about 46084.5038923064. The cubic root of 2123781499 is about 1285.3950142911.

The spelling of 2123781499 in words is "two billion, one hundred twenty-three million, seven hundred eighty-one thousand, four hundred ninety-nine".