21520047699 has 12 divisors (see below), whose sum is σ = 31095743016. Its totient is φ = 14341515552.

The previous prime is 21520047643. The next prime is 21520047709. The reversal of 21520047699 is 99674002512.

21520047699 is a `hidden beast` number, since 21 + 520 + 0 + 47 + 69 + 9 = 666.

It is not a de Polignac number, because 21520047699 - 2¹² = 21520043603 is a prime.

It is a super-2 number, since 2×21520047699² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21522047699) 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, 405529 + ... + 455514.

It is an arithmetic number, because the mean of its divisors is an integer number (2591311918).

Almost surely, 2^21520047699 is an apocalyptic number.

21520047699 is a deficient number, since it is larger than the sum of its proper divisors (9575695317).

21520047699 is a wasteful number, since it uses less digits than its factorization.

21520047699 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 863826 (or 863823 counting only the distinct ones).

The product of its (nonzero) digits is 272160, while the sum is 45.

The spelling of 21520047699 in words is "twenty-one billion, five hundred twenty million, forty-seven thousand, six hundred ninety-nine".