210161561021 has 4 divisors (see below), whose sum is σ = 210165845472. Its totient is φ = 210157276572.

The previous prime is 210161560997. The next prime is 210161561023. The reversal of 210161561021 is 120165161012.

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 210161561021 - 2¹⁰ = 210161559997 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 (210161561023) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2067785 + ... + 2167038.

It is an arithmetic number, because the mean of its divisors is an integer number (52541461368).

Almost surely, 2^210161561021 is an apocalyptic number.

It is an amenable number.

210161561021 is a deficient number, since it is larger than the sum of its proper divisors (4284451).

210161561021 is an equidigital number, since it uses as much as digits as its factorization.

210161561021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4284450.

The product of its (nonzero) digits is 720, while the sum is 26.

The spelling of 210161561021 in words is "two hundred ten billion, one hundred sixty-one million, five hundred sixty-one thousand, twenty-one".