21031772544 has 192 divisors, whose sum is σ = 62975718000. Its totient is φ = 6729117696.

The previous prime is 21031772537. The next prime is 21031772557. The reversal of 21031772544 is 44527713012.

21031772544 is a `hidden beast` number, since 2 + 10 + 31 + 7 + 72 + 544 = 666.

It is a tau number, because it is divible by the number of its divisors (192).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21031772499 and 21031772508.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5978274 + ... + 5981790.

Almost surely, 2^21031772544 is an apocalyptic number.

21031772544 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21031772544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31487859000).

21031772544 is an abundant number, since it is smaller than the sum of its proper divisors (41943945456).

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

21031772544 is a wasteful number, since it uses less digits than its factorization.

21031772544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3745 (or 3730 counting only the distinct ones).

The product of its (nonzero) digits is 47040, while the sum is 36.

The spelling of 21031772544 in words is "twenty-one billion, thirty-one million, seven hundred seventy-two thousand, five hundred forty-four".