21142253121 has 8 divisors (see below), whose sum is σ = 30752368224. Its totient is φ = 12813486720.

The previous prime is 21142253117. The next prime is 21142253137. The reversal of 21142253121 is 12135224112.

It is a happy number.

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

It is not a de Polignac number, because 21142253121 - 2² = 21142253117 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21142253091 and 21142253100.

It is not an unprimeable number, because it can be changed into a prime (21142253101) 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, 320337136 + ... + 320337201.

It is an arithmetic number, because the mean of its divisors is an integer number (3844046028).

Almost surely, 2^21142253121 is an apocalyptic number.

It is an amenable number.

21142253121 is a deficient number, since it is larger than the sum of its proper divisors (9610115103).

21142253121 is a wasteful number, since it uses less digits than its factorization.

21142253121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 640674351.

The product of its digits is 960, while the sum is 24.

Adding to 21142253121 its reverse (12135224112), we get a palindrome (33277477233).

The spelling of 21142253121 in words is "twenty-one billion, one hundred forty-two million, two hundred fifty-three thousand, one hundred twenty-one".