2121665730 has 32 divisors (see below), whose sum is σ = 5256258048. Its totient is φ = 547526400.

The previous prime is 2121665719. The next prime is 2121665731. The reversal of 2121665730 is 375661212.

It is a junction number, because it is equal to n+sod(n) for n = 2121665691 and 2121665700.

It is not an unprimeable number, because it can be changed into a prime (2121665731) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1139751 + ... + 1141610.

It is an arithmetic number, because the mean of its divisors is an integer number (164258064).

Almost surely, 2^2121665730 is an apocalyptic number.

2121665730 is an abundant number, since it is smaller than the sum of its proper divisors (3134592318).

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

2121665730 is a wasteful number, since it uses less digits than its factorization.

2121665730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2281402.

The product of its (nonzero) digits is 15120, while the sum is 33.

The square root of 2121665730 is about 46061.5428530135. The cubic root of 2121665730 is about 1284.9680239536.

The spelling of 2121665730 in words is "two billion, one hundred twenty-one million, six hundred sixty-five thousand, seven hundred thirty".