21121247773 has 8 divisors (see below), whose sum is σ = 21618912960. Its totient is φ = 20629143360.

The previous prime is 21121247747. The next prime is 21121247789. The reversal of 21121247773 is 37774212112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21121247773 is a prime.

It is a super-2 number, since 2×21121247773² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121247713) 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 7 ways as a sum of consecutive naturals, for example, 1382508 + ... + 1397701.

It is an arithmetic number, because the mean of its divisors is an integer number (2702364120).

Almost surely, 2^21121247773 is an apocalyptic number.

It is an amenable number.

21121247773 is a deficient number, since it is larger than the sum of its proper divisors (497665187).

21121247773 is a wasteful number, since it uses less digits than its factorization.

21121247773 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2780387.

The product of its digits is 32928, while the sum is 37.

Adding to 21121247773 its reverse (37774212112), we get a palindrome (58895459885).

The spelling of 21121247773 in words is "twenty-one billion, one hundred twenty-one million, two hundred forty-seven thousand, seven hundred seventy-three".