21126557523 has 8 divisors (see below), whose sum is σ = 28175449536. Its totient is φ = 14081018600.

The previous prime is 21126557489. The next prime is 21126557533. The reversal of 21126557523 is 32575562112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21126557523 - 2¹⁶ = 21126491987 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21126557533) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 823533 + ... + 848798.

It is an arithmetic number, because the mean of its divisors is an integer number (3521931192).

Almost surely, 2^21126557523 is an apocalyptic number.

21126557523 is a deficient number, since it is larger than the sum of its proper divisors (7048892013).

21126557523 is a wasteful number, since it uses less digits than its factorization.

21126557523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1676545.

The product of its digits is 126000, while the sum is 39.

The spelling of 21126557523 in words is "twenty-one billion, one hundred twenty-six million, five hundred fifty-seven thousand, five hundred twenty-three".