21226021515 has 16 divisors (see below), whose sum is σ = 37735149600. Its totient is φ = 11320544736.

The previous prime is 21226021507. The next prime is 21226021541. The reversal of 21226021515 is 51512062212.

21226021515 is a `hidden beast` number, since 2 + 1 + 2 + 2 + 602 + 1 + 51 + 5 = 666.

It is not a de Polignac number, because 21226021515 - 2³ = 21226021507 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 78614760 + ... + 78615029.

It is an arithmetic number, because the mean of its divisors is an integer number (2358446850).

Almost surely, 2^21226021515 is an apocalyptic number.

21226021515 is a deficient number, since it is larger than the sum of its proper divisors (16509128085).

21226021515 is a wasteful number, since it uses less digits than its factorization.

21226021515 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 157229803 (or 157229797 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 27.

Adding to 21226021515 its reverse (51512062212), we get a palindrome (72738083727).

The spelling of 21226021515 in words is "twenty-one billion, two hundred twenty-six million, twenty-one thousand, five hundred fifteen".