21520012076 has 12 divisors (see below), whose sum is σ = 38677859808. Its totient is φ = 10469194992.

The previous prime is 21520012069. The next prime is 21520012079. The reversal of 21520012076 is 67021002512.

It is a super-2 number, since 2×21520012076² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21520012079) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 72702596 + ... + 72702891.

It is an arithmetic number, because the mean of its divisors is an integer number (3223154984).

Almost surely, 2^21520012076 is an apocalyptic number.

It is an amenable number.

21520012076 is a deficient number, since it is larger than the sum of its proper divisors (17157847732).

21520012076 is a wasteful number, since it uses less digits than its factorization.

21520012076 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145405528 (or 145405526 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 26.

Adding to 21520012076 its reverse (67021002512), we get a palindrome (88541014588).

The spelling of 21520012076 in words is "twenty-one billion, five hundred twenty million, twelve thousand, seventy-six".