21240512121 has 8 divisors (see below), whose sum is σ = 29552016960. Its totient is φ = 13544674352.

The previous prime is 21240512119. The next prime is 21240512149. The reversal of 21240512121 is 12121504212.

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 21240512121 - 2¹ = 21240512119 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21240512101) 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, 153916686 + ... + 153916823.

It is an arithmetic number, because the mean of its divisors is an integer number (3694002120).

Almost surely, 2^21240512121 is an apocalyptic number.

It is an amenable number.

21240512121 is a deficient number, since it is larger than the sum of its proper divisors (8311504839).

21240512121 is a wasteful number, since it uses less digits than its factorization.

21240512121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 307833535.

The product of its (nonzero) digits is 320, while the sum is 21.

The spelling of 21240512121 in words is "twenty-one billion, two hundred forty million, five hundred twelve thousand, one hundred twenty-one".