21240504015 has 16 divisors (see below), whose sum is σ = 34042716288. Its totient is φ = 11308965536.

The previous prime is 21240504011. The next prime is 21240504053. The reversal of 21240504015 is 51040504212.

It is a cyclic number.

It is not a de Polignac number, because 21240504015 - 2² = 21240504011 is a prime.

It is a super-2 number, since 2×21240504015² (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 (21240504011) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1197357 + ... + 1214966.

It is an arithmetic number, because the mean of its divisors is an integer number (2127669768).

Almost surely, 2^21240504015 is an apocalyptic number.

21240504015 is a deficient number, since it is larger than the sum of its proper divisors (12802212273).

21240504015 is a wasteful number, since it uses less digits than its factorization.

21240504015 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2412918.

The product of its (nonzero) digits is 1600, while the sum is 24.

The spelling of 21240504015 in words is "twenty-one billion, two hundred forty million, five hundred four thousand, fifteen".