2171121551 has 4 divisors (see below), whose sum is σ = 2171376504. Its totient is φ = 2170866600.

The previous prime is 2171121539. The next prime is 2171121559. The reversal of 2171121551 is 1551211712.

2171121551 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 2171121551 - 2²² = 2166927247 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 2171121551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2171121559) 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, 114245 + ... + 131886.

It is an arithmetic number, because the mean of its divisors is an integer number (542844126).

Almost surely, 2^2171121551 is an apocalyptic number.

2171121551 is a deficient number, since it is larger than the sum of its proper divisors (254953).

2171121551 is an equidigital number, since it uses as much as digits as its factorization.

2171121551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254952.

The product of its digits is 700, while the sum is 26.

The square root of 2171121551 is about 46595.2953741040. The cubic root of 2171121551 is about 1294.8755963440.

The spelling of 2171121551 in words is "two billion, one hundred seventy-one million, one hundred twenty-one thousand, five hundred fifty-one".