201121621566 has 16 divisors (see below), whose sum is σ = 402255809424. Its totient is φ = 67038446144.

The previous prime is 201121621531. The next prime is 201121621573. The reversal of 201121621566 is 665126121102.

It is a super-2 number, since 2×201121621566² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 308751 + ... + 705386.

It is an arithmetic number, because the mean of its divisors is an integer number (25140988089).

Almost surely, 2^201121621566 is an apocalyptic number.

201121621566 is an abundant number, since it is smaller than the sum of its proper divisors (201134187858).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

201121621566 is a wasteful number, since it uses less digits than its factorization.

201121621566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1047195.

The product of its (nonzero) digits is 8640, while the sum is 33.

Adding to 201121621566 its reverse (665126121102), we get a palindrome (866247742668).

The spelling of 201121621566 in words is "two hundred one billion, one hundred twenty-one million, six hundred twenty-one thousand, five hundred sixty-six".