2170215661 has 4 divisors (see below), whose sum is σ = 2171245824. Its totient is φ = 2169185500.

The previous prime is 2170215659. The next prime is 2170215673. The reversal of 2170215661 is 1665120712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2170215661 - 2¹ = 2170215659 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2170210661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 511915 + ... + 516136.

It is an arithmetic number, because the mean of its divisors is an integer number (542811456).

Almost surely, 2^2170215661 is an apocalyptic number.

It is an amenable number.

2170215661 is a deficient number, since it is larger than the sum of its proper divisors (1030163).

2170215661 is a wasteful number, since it uses less digits than its factorization.

2170215661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1030162.

The product of its (nonzero) digits is 5040, while the sum is 31.

The square root of 2170215661 is about 46585.5735287224. The cubic root of 2170215661 is about 1294.6954777572.

The spelling of 2170215661 in words is "two billion, one hundred seventy million, two hundred fifteen thousand, six hundred sixty-one".