2121906571 has 4 divisors (see below), whose sum is σ = 2123269200. Its totient is φ = 2120543944.

The previous prime is 2121906551. The next prime is 2121906587. The reversal of 2121906571 is 1756091212.

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 2121906571 - 2²³ = 2113517963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2121906551) 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, 678976 + ... + 682093.

It is an arithmetic number, because the mean of its divisors is an integer number (530817300).

Almost surely, 2^2121906571 is an apocalyptic number.

2121906571 is a deficient number, since it is larger than the sum of its proper divisors (1362629).

2121906571 is a wasteful number, since it uses less digits than its factorization.

2121906571 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1362628.

The product of its (nonzero) digits is 7560, while the sum is 34.

The square root of 2121906571 is about 46064.1571180891. The cubic root of 2121906571 is about 1285.0166431855.

Adding to 2121906571 its reverse (1756091212), we get a palindrome (3877997783).

The spelling of 2121906571 in words is "two billion, one hundred twenty-one million, nine hundred six thousand, five hundred seventy-one".