21112472477 has 4 divisors (see below), whose sum is σ = 21112772316. Its totient is φ = 21112172640.

The previous prime is 21112472471. The next prime is 21112472509. The reversal of 21112472477 is 77427421112.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 4776053881 + 16336418596 = 69109^2 + 127814^2 .

It is a cyclic number.

It is not a de Polignac number, because 21112472477 - 2³⁴ = 3932603293 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21112472477.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112472471) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19577 + ... + 206417.

It is an arithmetic number, because the mean of its divisors is an integer number (5278193079).

Almost surely, 2^21112472477 is an apocalyptic number.

It is an amenable number.

21112472477 is a deficient number, since it is larger than the sum of its proper divisors (299839).

21112472477 is a wasteful number, since it uses less digits than its factorization.

21112472477 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 299838.

The product of its digits is 43904, while the sum is 38.

Adding to 21112472477 its reverse (77427421112), we get a palindrome (98539893589).

The spelling of 21112472477 in words is "twenty-one billion, one hundred twelve million, four hundred seventy-two thousand, four hundred seventy-seven".