2121735905 has 4 divisors (see below), whose sum is σ = 2546083092. Its totient is φ = 1697388720.

The previous prime is 2121735877. The next prime is 2121735907. The reversal of 2121735905 is 5095371212.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1533818896 + 587917009 = 39164^2 + 24247^2 .

It is not a de Polignac number, because 2121735905 - 2¹² = 2121731809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2121735907) 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, 212173586 + ... + 212173595.

It is an arithmetic number, because the mean of its divisors is an integer number (636520773).

Almost surely, 2^2121735905 is an apocalyptic number.

It is an amenable number.

2121735905 is a deficient number, since it is larger than the sum of its proper divisors (424347187).

2121735905 is an equidigital number, since it uses as much as digits as its factorization.

2121735905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 424347186.

The product of its (nonzero) digits is 18900, while the sum is 35.

The square root of 2121735905 is about 46062.3045993142. The cubic root of 2121735905 is about 1284.9821907528.

The spelling of 2121735905 in words is "two billion, one hundred twenty-one million, seven hundred thirty-five thousand, nine hundred five".