21503250015 has 32 divisors (see below), whose sum is σ = 37058890176. Its totient is φ = 10584176640.

The previous prime is 21503250011. The next prime is 21503250031. The reversal of 21503250015 is 51005230512.

It is a happy number.

It is not a de Polignac number, because 21503250015 - 2² = 21503250011 is a prime.

It is a super-2 number, since 2×21503250015² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21503250011) 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 31 ways as a sum of consecutive naturals, for example, 1756897 + ... + 1769093.

It is an arithmetic number, because the mean of its divisors is an integer number (1158090318).

Almost surely, 2^21503250015 is an apocalyptic number.

21503250015 is a deficient number, since it is larger than the sum of its proper divisors (15555640161).

21503250015 is a wasteful number, since it uses less digits than its factorization.

21503250015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21259.

The product of its (nonzero) digits is 1500, while the sum is 24.

Adding to 21503250015 its reverse (51005230512), we get a palindrome (72508480527).

The spelling of 21503250015 in words is "twenty-one billion, five hundred three million, two hundred fifty thousand, fifteen".