21242551027 has 4 divisors (see below), whose sum is σ = 21318147576. Its totient is φ = 21166954480.

The previous prime is 21242551013. The next prime is 21242551039. The reversal of 21242551027 is 72015524212.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21242551027 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21242551027.

It is not an unprimeable number, because it can be changed into a prime (21242551727) 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, 37797853 + ... + 37798414.

It is an arithmetic number, because the mean of its divisors is an integer number (5329536894).

Almost surely, 2^21242551027 is an apocalyptic number.

21242551027 is a deficient number, since it is larger than the sum of its proper divisors (75596549).

21242551027 is an equidigital number, since it uses as much as digits as its factorization.

21242551027 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75596548.

The product of its (nonzero) digits is 11200, while the sum is 31.

The spelling of 21242551027 in words is "twenty-one billion, two hundred forty-two million, five hundred fifty-one thousand, twenty-seven".