21147126425 has 12 divisors (see below), whose sum is σ = 26374016940. Its totient is φ = 16819907520.

The previous prime is 21147126397. The next prime is 21147126479. The reversal of 21147126425 is 52462174112.

It can be written as a sum of positive squares in 6 ways, for example, as 116035984 + 21031090441 = 10772^2 + 145021^2 .

It is not a de Polignac number, because 21147126425 - 2¹² = 21147122329 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2440430 + ... + 2449079.

It is an arithmetic number, because the mean of its divisors is an integer number (2197834745).

Almost surely, 2^21147126425 is an apocalyptic number.

21147126425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21147126425 is a deficient number, since it is larger than the sum of its proper divisors (5226890515).

21147126425 is a wasteful number, since it uses less digits than its factorization.

21147126425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4889692 (or 4889687 counting only the distinct ones).

The product of its digits is 26880, while the sum is 35.

The spelling of 21147126425 in words is "twenty-one billion, one hundred forty-seven million, one hundred twenty-six thousand, four hundred twenty-five".