2154197871 has 48 divisors (see below), whose sum is σ = 3730461696. Its totient is φ = 1171196928.

The previous prime is 2154197867. The next prime is 2154197873. The reversal of 2154197871 is 1787914512.

It is a happy number.

2154197871 is a `hidden beast` number, since 21 + 541 + 9 + 7 + 87 + 1 = 666.

2154197871 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 2154197871 - 2² = 2154197867 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2154197873) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 275806 + ... + 283508.

It is an arithmetic number, because the mean of its divisors is an integer number (77717952).

Almost surely, 2^2154197871 is an apocalyptic number.

2154197871 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

2154197871 is a deficient number, since it is larger than the sum of its proper divisors (1576263825).

2154197871 is a wasteful number, since it uses less digits than its factorization.

2154197871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7932 (or 7929 counting only the distinct ones).

The product of its digits is 141120, while the sum is 45.

The square root of 2154197871 is about 46413.3372103321. The cubic root of 2154197871 is about 1291.5023401876.

The spelling of 2154197871 in words is "two billion, one hundred fifty-four million, one hundred ninety-seven thousand, eight hundred seventy-one".