21199977551772 has 36 divisors (see below), whose sum is σ = 53643682624896. Its totient is φ = 7059426153600.

The previous prime is 21199977551771. The next prime is 21199977551777. The reversal of 21199977551772 is 27715577999112.

21199977551772 is a `hidden beast` number, since 2 + 1 + 19 + 9 + 97 + 7 + 5 + 517 + 7 + 2 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21199977551772.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21199977551771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 301340604 + ... + 301410947.

It is an arithmetic number, because the mean of its divisors is an integer number (1490102295136).

Almost surely, 2^{21199977551772} is an apocalyptic number.

It is an amenable number.

21199977551772 is an abundant number, since it is smaller than the sum of its proper divisors (32443705073124).

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

21199977551772 is a wasteful number, since it uses less digits than its factorization.

21199977551772 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 602752538 (or 602752533 counting only the distinct ones).

The product of its digits is 175032900, while the sum is 72.

It can be divided in two parts, 2119997 and 7551772, that added together give a palindrome (9671769).

The spelling of 21199977551772 in words is "twenty-one trillion, one hundred ninety-nine billion, nine hundred seventy-seven million, five hundred fifty-one thousand, seven hundred seventy-two".