21388025651 has 4 divisors (see below), whose sum is σ = 21393758832. Its totient is φ = 21382292472.

The previous prime is 21388025629. The next prime is 21388025693. The reversal of 21388025651 is 15652088312.

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 21388025651 - 2¹⁴ = 21388009267 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21388025599 and 21388025608.

It is not an unprimeable number, because it can be changed into a prime (21388025251) 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, 2860991 + ... + 2868456.

It is an arithmetic number, because the mean of its divisors is an integer number (5348439708).

Almost surely, 2^21388025651 is an apocalyptic number.

21388025651 is a deficient number, since it is larger than the sum of its proper divisors (5733181).

21388025651 is an equidigital number, since it uses as much as digits as its factorization.

21388025651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5733180.

The product of its (nonzero) digits is 115200, while the sum is 41.

The spelling of 21388025651 in words is "twenty-one billion, three hundred eighty-eight million, twenty-five thousand, six hundred fifty-one".