21620687769 has 24 divisors (see below), whose sum is σ = 32602969152. Its totient is φ = 13780646880.

The previous prime is 21620687749. The next prime is 21620687773. The reversal of 21620687769 is 96778602612.

21620687769 is a `hidden beast` number, since 2 + 1 + 620 + 6 + 8 + 7 + 7 + 6 + 9 = 666.

It is not a de Polignac number, because 21620687769 - 2¹⁷ = 21620556697 is a prime.

It is a super-2 number, since 2×21620687769² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21620687719) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 439714 + ... + 486404.

It is an arithmetic number, because the mean of its divisors is an integer number (1358457048).

Almost surely, 2^21620687769 is an apocalyptic number.

It is an amenable number.

21620687769 is a deficient number, since it is larger than the sum of its proper divisors (10982281383).

21620687769 is a wasteful number, since it uses less digits than its factorization.

21620687769 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48957 (or 48954 counting only the distinct ones).

The product of its (nonzero) digits is 3048192, while the sum is 54.

The spelling of 21620687769 in words is "twenty-one billion, six hundred twenty million, six hundred eighty-seven thousand, seven hundred sixty-nine".