21121736385 has 16 divisors (see below), whose sum is σ = 34884933120. Its totient is φ = 10901541120.

The previous prime is 21121736297. The next prime is 21121736387. The reversal of 21121736385 is 58363712112.

It is a happy number.

It is not a de Polignac number, because 21121736385 - 2¹⁴ = 21121720001 is a prime.

It is a super-2 number, since 2×21121736385² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21121736387) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22711080 + ... + 22712009.

It is an arithmetic number, because the mean of its divisors is an integer number (2180308320).

Almost surely, 2^21121736385 is an apocalyptic number.

It is an amenable number.

21121736385 is a deficient number, since it is larger than the sum of its proper divisors (13763196735).

21121736385 is a wasteful number, since it uses less digits than its factorization.

21121736385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45423128.

The product of its digits is 60480, while the sum is 39.

The spelling of 21121736385 in words is "twenty-one billion, one hundred twenty-one million, seven hundred thirty-six thousand, three hundred eighty-five".