21252211515 has 64 divisors (see below), whose sum is σ = 38873088000. Its totient is φ = 11008213632.

The previous prime is 21252211507. The next prime is 21252211559. The reversal of 21252211515 is 51511225212.

21252211515 is a `hidden beast` number, since 2 + 12 + 522 + 115 + 15 = 666.

It is not a de Polignac number, because 21252211515 - 2³ = 21252211507 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 (19) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2988454 + ... + 2995556.

It is an arithmetic number, because the mean of its divisors is an integer number (607392000).

Almost surely, 2^21252211515 is an apocalyptic number.

21252211515 is a deficient number, since it is larger than the sum of its proper divisors (17620876485).

21252211515 is a wasteful number, since it uses less digits than its factorization.

21252211515 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7753 (or 7747 counting only the distinct ones).

The product of its digits is 2000, while the sum is 27.

Adding to 21252211515 its reverse (51511225212), we get a palindrome (72763436727).

The spelling of 21252211515 in words is "twenty-one billion, two hundred fifty-two million, two hundred eleven thousand, five hundred fifteen".