21515523140047 has 2 divisors, whose sum is σ = 21515523140048. Its totient is φ = 21515523140046.

The previous prime is 21515523139969. The next prime is 21515523140071. The reversal of 21515523140047 is 74004132551512.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21515523140047 - 2⁷ = 21515523139919 is a prime.

It is a super-4 number, since 4×21515523140047⁴ (a number of 54 digits) contains 4444 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21515523139991 and 21515523140009.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21515523140087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10757761570023 + 10757761570024.

It is an arithmetic number, because the mean of its divisors is an integer number (10757761570024).

Almost surely, 2^{21515523140047} is an apocalyptic number.

21515523140047 is a deficient number, since it is larger than the sum of its proper divisors (1).

21515523140047 is an equidigital number, since it uses as much as digits as its factorization.

21515523140047 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 168000, while the sum is 40.

Adding to 21515523140047 its reverse (74004132551512), we get a palindrome (95519655691559).

The spelling of 21515523140047 in words is "twenty-one trillion, five hundred fifteen billion, five hundred twenty-three million, one hundred forty thousand, forty-seven".