21661465732280 has 64 divisors (see below), whose sum is σ = 53191708836480. Its totient is φ = 7873540099200.

The previous prime is 21661465732273. The next prime is 21661465732327. The reversal of 21661465732280 is 8223756416612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9455306 + ... + 11520665.

It is an arithmetic number, because the mean of its divisors is an integer number (831120450570).

Almost surely, 2^{21661465732280} is an apocalyptic number.

21661465732280 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21661465732280 is an abundant number, since it is smaller than the sum of its proper divisors (31530243104200).

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

21661465732280 is a wasteful number, since it uses less digits than its factorization.

21661465732280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20978340 (or 20978336 counting only the distinct ones).

The product of its (nonzero) digits is 5806080, while the sum is 53.

The spelling of 21661465732280 in words is "twenty-one trillion, six hundred sixty-one billion, four hundred sixty-five million, seven hundred thirty-two thousand, two hundred eighty".