21774365520 has 80 divisors (see below), whose sum is σ = 68355029760. Its totient is φ = 5732992512.

The previous prime is 21774365461. The next prime is 21774365549. The reversal of 21774365520 is 2556347712.

It is a tau number, because it is divible by the number of its divisors (80).

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, 555259 + ... + 593178.

It is an arithmetic number, because the mean of its divisors is an integer number (854437872).

Almost surely, 2^21774365520 is an apocalyptic number.

21774365520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21774365520 is an abundant number, since it is smaller than the sum of its proper divisors (46580664240).

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

21774365520 is a wasteful number, since it uses less digits than its factorization.

21774365520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1148532 (or 1148526 counting only the distinct ones).

The product of its (nonzero) digits is 352800, while the sum is 42.

The spelling of 21774365520 in words is "twenty-one billion, seven hundred seventy-four million, three hundred sixty-five thousand, five hundred twenty".