2720161521 has 80 divisors (see below), whose sum is σ = 5097426048. Its totient is φ = 1404345600.

The previous prime is 2720161511. The next prime is 2720161537. The reversal of 2720161521 is 1251610272.

2720161521 is a `hidden beast` number, since 2 + 7 + 20 + 1 + 615 + 21 = 666.

It is not a de Polignac number, because 2720161521 - 2⁵ = 2720161489 is a prime.

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

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2720161501) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 1077741 + ... + 1080261.

Almost surely, 2^2720161521 is an apocalyptic number.

2720161521 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

2720161521 is a deficient number, since it is larger than the sum of its proper divisors (2377264527).

2720161521 is a wasteful number, since it uses less digits than its factorization.

2720161521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2724 (or 2715 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 27.

The square root of 2720161521 is about 52155.1677305327. The cubic root of 2720161521 is about 1395.9340397416.

Adding to 2720161521 its reverse (1251610272), we get a palindrome (3971771793).

The spelling of 2720161521 in words is "two billion, seven hundred twenty million, one hundred sixty-one thousand, five hundred twenty-one".