21400520064725 has 6 divisors (see below), whose sum is σ = 26536644880290. Its totient is φ = 17120416051760.

The previous prime is 21400520064673. The next prime is 21400520064731. The reversal of 21400520064725 is 52746002500412.

It can be written as a sum of positive squares in 3 ways, for example, as 546264375409 + 20854255689316 = 739097^2 + 4566646^2 .

It is not a de Polignac number, because 21400520064725 - 2⁶ = 21400520064661 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 428010401270 + ... + 428010401319.

It is an arithmetic number, because the mean of its divisors is an integer number (4422774146715).

Almost surely, 2^{21400520064725} is an apocalyptic number.

21400520064725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21400520064725 is a deficient number, since it is larger than the sum of its proper divisors (5136124815565).

21400520064725 is an equidigital number, since it uses as much as digits as its factorization.

21400520064725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 856020802599 (or 856020802594 counting only the distinct ones).

The product of its (nonzero) digits is 134400, while the sum is 38.

The spelling of 21400520064725 in words is "twenty-one trillion, four hundred billion, five hundred twenty million, sixty-four thousand, seven hundred twenty-five".