2155221551 has 8 divisors (see below), whose sum is σ = 2465984640. Its totient is φ = 1845177048.

The previous prime is 2155221517. The next prime is 2155221577. The reversal of 2155221551 is 1551225512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 2155221551 - 2⁶ = 2155221487 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2155221581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 173201 + ... + 185226.

It is an arithmetic number, because the mean of its divisors is an integer number (308248080).

Almost surely, 2^2155221551 is an apocalyptic number.

2155221551 is a deficient number, since it is larger than the sum of its proper divisors (310763089).

2155221551 is an equidigital number, since it uses as much as digits as its factorization.

2155221551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 359293.

The product of its digits is 5000, while the sum is 29.

The square root of 2155221551 is about 46424.3637651611. The cubic root of 2155221551 is about 1291.7068827955.

The spelling of 2155221551 in words is "two billion, one hundred fifty-five million, two hundred twenty-one thousand, five hundred fifty-one".