21458670521 has 4 divisors (see below), whose sum is σ = 21667007232. Its totient is φ = 21250333812.

The previous prime is 21458670491. The next prime is 21458670523. The reversal of 21458670521 is 12507685412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21458670521 - 2¹⁰ = 21458669497 is a prime.

It is a super-2 number, since 2×21458670521² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21458670523) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 104168201 + ... + 104168406.

It is an arithmetic number, because the mean of its divisors is an integer number (5416751808).

Almost surely, 2^21458670521 is an apocalyptic number.

It is an amenable number.

21458670521 is a deficient number, since it is larger than the sum of its proper divisors (208336711).

21458670521 is a wasteful number, since it uses less digits than its factorization.

21458670521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 208336710.

The product of its (nonzero) digits is 134400, while the sum is 41.

The spelling of 21458670521 in words is "twenty-one billion, four hundred fifty-eight million, six hundred seventy thousand, five hundred twenty-one".