2166515021 has 8 divisors (see below), whose sum is σ = 2380476000. Its totient is φ = 1955388240.

The previous prime is 2166515017. The next prime is 2166515023. The reversal of 2166515021 is 1205156612.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 2166515021 - 2² = 2166515017 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2166515023) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 706946 + ... + 710003.

It is an arithmetic number, because the mean of its divisors is an integer number (297559500).

Almost surely, 2^2166515021 is an apocalyptic number.

It is an amenable number.

2166515021 is a deficient number, since it is larger than the sum of its proper divisors (213960979).

2166515021 is a wasteful number, since it uses less digits than its factorization.

2166515021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1417099.

The product of its (nonzero) digits is 3600, while the sum is 29.

The square root of 2166515021 is about 46545.8378482975. The cubic root of 2166515021 is about 1293.9591565009.

The spelling of 2166515021 in words is "two billion, one hundred sixty-six million, five hundred fifteen thousand, twenty-one".