2145207720 has 64 divisors (see below), whose sum is σ = 6657552000. Its totient is φ = 552328448.

The previous prime is 2145207709. The next prime is 2145207733. The reversal of 2145207720 is 277025412.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 304740 + ... + 311699.

It is an arithmetic number, because the mean of its divisors is an integer number (104024250).

Almost surely, 2^2145207720 is an apocalyptic number.

2145207720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2145207720 is an abundant number, since it is smaller than the sum of its proper divisors (4512344280).

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

2145207720 is a wasteful number, since it uses less digits than its factorization.

2145207720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 616482 (or 616478 counting only the distinct ones).

The product of its (nonzero) digits is 7840, while the sum is 30.

The square root of 2145207720 is about 46316.3871648038. The cubic root of 2145207720 is about 1289.7032187889.

The spelling of 2145207720 in words is "two billion, one hundred forty-five million, two hundred seven thousand, seven hundred twenty".