21661042031144 has 32 divisors (see below), whose sum is σ = 41706597150720. Its totient is φ = 10542500894016.

The previous prime is 21661042031143. The next prime is 21661042031183. The reversal of 21661042031144 is 44113024016612.

It is not an unprimeable number, because it can be changed into a prime (21661042031143) 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, 201077504 + ... + 201185199.

It is an arithmetic number, because the mean of its divisors is an integer number (1303331160960).

Almost surely, 2^{21661042031144} is an apocalyptic number.

It is an amenable number.

21661042031144 is a deficient number, since it is larger than the sum of its proper divisors (20045555119576).

21661042031144 is a wasteful number, since it uses less digits than its factorization.

21661042031144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 402262889 (or 402262885 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 35.

Adding to 21661042031144 its reverse (44113024016612), we get a palindrome (65774066047756).

The spelling of 21661042031144 in words is "twenty-one trillion, six hundred sixty-one billion, forty-two million, thirty-one thousand, one hundred forty-four".