21661032154643 has 24 divisors (see below), whose sum is σ = 25264261797840. Its totient is φ = 18517433565120.

The previous prime is 21661032154631. The next prime is 21661032154673. The reversal of 21661032154643 is 34645123016612.

It is not a de Polignac number, because 21661032154643 - 2¹⁴ = 21661032138259 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21661032154594 and 21661032154603.

It is not an unprimeable number, because it can be changed into a prime (21661032154603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 298897433 + ... + 298969893.

It is an arithmetic number, because the mean of its divisors is an integer number (1052677574910).

Almost surely, 2^{21661032154643} is an apocalyptic number.

21661032154643 is a deficient number, since it is larger than the sum of its proper divisors (3603229643197).

21661032154643 is a wasteful number, since it uses less digits than its factorization.

21661032154643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88547 (or 88540 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 44.

The spelling of 21661032154643 in words is "twenty-one trillion, six hundred sixty-one billion, thirty-two million, one hundred fifty-four thousand, six hundred forty-three".