210554421661 has 8 divisors (see below), whose sum is σ = 215650335744. Its totient is φ = 205500107280.

The previous prime is 210554421643. The next prime is 210554421743. The reversal of 210554421661 is 166124455012.

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 210554421661 - 2¹¹ = 210554419613 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 210554421661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (210554427661) 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, 10389681 + ... + 10409926.

It is an arithmetic number, because the mean of its divisors is an integer number (26956291968).

Almost surely, 2^210554421661 is an apocalyptic number.

It is an amenable number.

210554421661 is a deficient number, since it is larger than the sum of its proper divisors (5095914083).

210554421661 is a wasteful number, since it uses less digits than its factorization.

210554421661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20799851.

The product of its (nonzero) digits is 57600, while the sum is 37.

Adding to 210554421661 its reverse (166124455012), we get a palindrome (376678876673).

The spelling of 210554421661 in words is "two hundred ten billion, five hundred fifty-four million, four hundred twenty-one thousand, six hundred sixty-one".