21523404143551 has 2 divisors, whose sum is σ = 21523404143552. Its totient is φ = 21523404143550.

The previous prime is 21523404143531. The next prime is 21523404143573. The reversal of 21523404143551 is 15534140432512.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21523404143551 is a prime.

It is a super-3 number, since 3×21523404143551³ (a number of 41 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21523404143531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10761702071775 + 10761702071776.

It is an arithmetic number, because the mean of its divisors is an integer number (10761702071776).

Almost surely, 2^{21523404143551} is an apocalyptic number.

21523404143551 is a deficient number, since it is larger than the sum of its proper divisors (1).

21523404143551 is an equidigital number, since it uses as much as digits as its factorization.

21523404143551 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288000, while the sum is 40.

The spelling of 21523404143551 in words is "twenty-one trillion, five hundred twenty-three billion, four hundred four million, one hundred forty-three thousand, five hundred fifty-one".