2171561520 has 80 divisors (see below), whose sum is σ = 6737783040. Its totient is φ = 578572032.

The previous prime is 2171561503. The next prime is 2171561551. The reversal of 2171561520 is 251651712.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 324771 + ... + 331389.

It is an arithmetic number, because the mean of its divisors is an integer number (84222288).

Almost surely, 2^2171561520 is an apocalyptic number.

2171561520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2171561520 is an abundant number, since it is smaller than the sum of its proper divisors (4566221520).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2171561520 is a wasteful number, since it uses less digits than its factorization.

2171561520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8002 (or 7996 counting only the distinct ones).

The product of its (nonzero) digits is 4200, while the sum is 30.

The square root of 2171561520 is about 46600.0163090100. The cubic root of 2171561520 is about 1294.9630575370.

The spelling of 2171561520 in words is "two billion, one hundred seventy-one million, five hundred sixty-one thousand, five hundred twenty".