2155021551 has 16 divisors (see below), whose sum is σ = 3246739200. Its totient is φ = 1412329464.

The previous prime is 2155021543. The next prime is 2155021559. The reversal of 2155021551 is 1551205512.

2155021551 is a `hidden beast` number, since 2 + 1 + 5 + 502 + 155 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (2155021543) and next prime (2155021559).

It is not a de Polignac number, because 2155021551 - 2³ = 2155021543 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2155021559) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 674811 + ... + 677996.

It is an arithmetic number, because the mean of its divisors is an integer number (202921200).

Almost surely, 2^2155021551 is an apocalyptic number.

2155021551 is a deficient number, since it is larger than the sum of its proper divisors (1091717649).

2155021551 is a wasteful number, since it uses less digits than its factorization.

2155021551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1352875 (or 1352869 counting only the distinct ones).

The product of its (nonzero) digits is 2500, while the sum is 27.

The square root of 2155021551 is about 46422.2096738188. The cubic root of 2155021551 is about 1291.6669256709. Note that the first 3 decimals are identical.

The spelling of 2155021551 in words is "two billion, one hundred fifty-five million, twenty-one thousand, five hundred fifty-one".