21515050142015 has 4 divisors (see below), whose sum is σ = 25818060170424. Its totient is φ = 17212040113608.

The previous prime is 21515050141979. The next prime is 21515050142021. The reversal of 21515050142015 is 51024105051512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21515050142015 is a prime.

It is a super-2 number, since 2×21515050142015² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2151505014197 + ... + 2151505014206.

It is an arithmetic number, because the mean of its divisors is an integer number (6454515042606).

Almost surely, 2^{21515050142015} is an apocalyptic number.

21515050142015 is a deficient number, since it is larger than the sum of its proper divisors (4303010028409).

21515050142015 is an equidigital number, since it uses as much as digits as its factorization.

21515050142015 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4303010028408.

The product of its (nonzero) digits is 10000, while the sum is 32.

Adding to 21515050142015 its reverse (51024105051512), we get a palindrome (72539155193527).

The spelling of 21515050142015 in words is "twenty-one trillion, five hundred fifteen billion, fifty million, one hundred forty-two thousand, fifteen".