21001523211751 has 2 divisors, whose sum is σ = 21001523211752. Its totient is φ = 21001523211750.

The previous prime is 21001523211749. The next prime is 21001523211829. The reversal of 21001523211751 is 15711232510012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21001523211751 - 2¹ = 21001523211749 is a prime.

Together with 21001523211749, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21001523212751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500761605875 + 10500761605876.

It is an arithmetic number, because the mean of its divisors is an integer number (10500761605876).

Almost surely, 2^{21001523211751} is an apocalyptic number.

21001523211751 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001523211751 is an equidigital number, since it uses as much as digits as its factorization.

21001523211751 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4200, while the sum is 31.

Adding to 21001523211751 its reverse (15711232510012), we get a palindrome (36712755721763).

The spelling of 21001523211751 in words is "twenty-one trillion, one billion, five hundred twenty-three million, two hundred eleven thousand, seven hundred fifty-one".