21315010523 has 2 divisors, whose sum is σ = 21315010524. Its totient is φ = 21315010522.

The previous prime is 21315010489. The next prime is 21315010699. The reversal of 21315010523 is 32501051312.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21315010523 - 2⁶ = 21315010459 is a prime.

It is not a weakly prime, because it can be changed into another prime (21315010723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10657505261 + 10657505262.

It is an arithmetic number, because the mean of its divisors is an integer number (10657505262).

Almost surely, 2^21315010523 is an apocalyptic number.

21315010523 is a deficient number, since it is larger than the sum of its proper divisors (1).

21315010523 is an equidigital number, since it uses as much as digits as its factorization.

21315010523 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 900, while the sum is 23.

Adding to 21315010523 its reverse (32501051312), we get a palindrome (53816061835).

The spelling of 21315010523 in words is "twenty-one billion, three hundred fifteen million, ten thousand, five hundred twenty-three".