21425655614521 has 4 divisors (see below), whose sum is σ = 21425686994944. Its totient is φ = 21425624234100.

The previous prime is 21425655614491. The next prime is 21425655614551. The reversal of 21425655614521 is 12541655652412.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (21425655614491) and next prime (21425655614551).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21425655614521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21425655614551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14642745 + ... + 16039366.

It is an arithmetic number, because the mean of its divisors is an integer number (5356421748736).

Almost surely, 2^{21425655614521} is an apocalyptic number.

It is an amenable number.

21425655614521 is a deficient number, since it is larger than the sum of its proper divisors (31380423).

21425655614521 is an equidigital number, since it uses as much as digits as its factorization.

21425655614521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31380422.

The product of its digits is 2880000, while the sum is 49.

The spelling of 21425655614521 in words is "twenty-one trillion, four hundred twenty-five billion, six hundred fifty-five million, six hundred fourteen thousand, five hundred twenty-one".