21661020450616 has 32 divisors (see below), whose sum is σ = 41243147225280. Its totient is φ = 10664032752000.

The previous prime is 21661020450577. The next prime is 21661020450679. The reversal of 21661020450616 is 61605402016612.

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, 73909536 + ... + 74202031.

It is an arithmetic number, because the mean of its divisors is an integer number (1288848350790).

Almost surely, 2^{21661020450616} is an apocalyptic number.

It is an amenable number.

21661020450616 is a deficient number, since it is larger than the sum of its proper divisors (19582126774664).

21661020450616 is a wasteful number, since it uses less digits than its factorization.

21661020450616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 148111855 (or 148111851 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 40.

The spelling of 21661020450616 in words is "twenty-one trillion, six hundred sixty-one billion, twenty million, four hundred fifty thousand, six hundred sixteen".