21642243661541 has 16 divisors (see below), whose sum is σ = 22228515953280. Its totient is φ = 21058807150080.

The previous prime is 21642243661523. The next prime is 21642243661543. The reversal of 21642243661541 is 14516634224612.

It is a cyclic number.

It is not a de Polignac number, because 21642243661541 - 2³⁸ = 21367365754597 is a prime.

It is a super-4 number, since 4×21642243661541⁴ (a number of 54 digits) contains 4444 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21642243661543) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 31689650 + ... + 32365388.

It is an arithmetic number, because the mean of its divisors is an integer number (1389282247080).

Almost surely, 2^{21642243661541} is an apocalyptic number.

It is an amenable number.

21642243661541 is a deficient number, since it is larger than the sum of its proper divisors (586272291739).

21642243661541 is a wasteful number, since it uses less digits than its factorization.

21642243661541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 677836.

The product of its digits is 1658880, while the sum is 47.

The spelling of 21642243661541 in words is "twenty-one trillion, six hundred forty-two billion, two hundred forty-three million, six hundred sixty-one thousand, five hundred forty-one".