21142501251 has 4 divisors (see below), whose sum is σ = 28190001672. Its totient is φ = 14095000832.

The previous prime is 21142501249. The next prime is 21142501279. The reversal of 21142501251 is 15210524112.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21142501251 - 2¹ = 21142501249 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21142501951) 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, 3523750206 + ... + 3523750211.

It is an arithmetic number, because the mean of its divisors is an integer number (7047500418).

Almost surely, 2^21142501251 is an apocalyptic number.

21142501251 is a deficient number, since it is larger than the sum of its proper divisors (7047500421).

21142501251 is an equidigital number, since it uses as much as digits as its factorization.

21142501251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7047500420.

The product of its (nonzero) digits is 800, while the sum is 24.

The spelling of 21142501251 in words is "twenty-one billion, one hundred forty-two million, five hundred one thousand, two hundred fifty-one".