21522001523 has 4 divisors (see below), whose sum is σ = 23478547128. Its totient is φ = 19565455920.

The previous prime is 21522001493. The next prime is 21522001559. The reversal of 21522001523 is 32510022512.

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

It is a cyclic number.

It is not a de Polignac number, because 21522001523 - 2¹⁴ = 21521985139 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21522001573) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 978272786 + ... + 978272807.

It is an arithmetic number, because the mean of its divisors is an integer number (5869636782).

Almost surely, 2^21522001523 is an apocalyptic number.

21522001523 is a deficient number, since it is larger than the sum of its proper divisors (1956545605).

21522001523 is a wasteful number, since it uses less digits than its factorization.

21522001523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1956545604.

The product of its (nonzero) digits is 1200, while the sum is 23.

The spelling of 21522001523 in words is "twenty-one billion, five hundred twenty-two million, one thousand, five hundred twenty-three".