2121722755 has 4 divisors (see below), whose sum is σ = 2546067312. Its totient is φ = 1697378200.

The previous prime is 2121722719. The next prime is 2121722831. The reversal of 2121722755 is 5572271212.

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

It is not a de Polignac number, because 2121722755 - 2¹⁵ = 2121689987 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2121722755.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 212172271 + ... + 212172280.

It is an arithmetic number, because the mean of its divisors is an integer number (636516828).

Almost surely, 2^2121722755 is an apocalyptic number.

2121722755 is a deficient number, since it is larger than the sum of its proper divisors (424344557).

2121722755 is an equidigital number, since it uses as much as digits as its factorization.

2121722755 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 424344556.

The product of its digits is 19600, while the sum is 34.

The square root of 2121722755 is about 46062.1618576462. The cubic root of 2121722755 is about 1284.9795360789.

Adding to 2121722755 its reverse (5572271212), we get a palindrome (7693993967).

The spelling of 2121722755 in words is "two billion, one hundred twenty-one million, seven hundred twenty-two thousand, seven hundred fifty-five".