21512421342425 has 12 divisors (see below), whose sum is σ = 28727356500780. Its totient is φ = 15886095760320.

The previous prime is 21512421342383. The next prime is 21512421342431. The reversal of 21512421342425 is 52424312421512.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 3816197413081 + 17696223929344 = 1953509^2 + 4206688^2 .

It is not a de Polignac number, because 21512421342425 - 2²⁴ = 21512404565209 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 33096032510 + ... + 33096033159.

It is an arithmetic number, because the mean of its divisors is an integer number (2393946375065).

Almost surely, 2^{21512421342425} is an apocalyptic number.

21512421342425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21512421342425 is a deficient number, since it is larger than the sum of its proper divisors (7214935158355).

21512421342425 is a wasteful number, since it uses less digits than its factorization.

21512421342425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66192065692 (or 66192065687 counting only the distinct ones).

The product of its digits is 153600, while the sum is 38.

Adding to 21512421342425 its reverse (52424312421512), we get a palindrome (73936733763937).

The spelling of 21512421342425 in words is "twenty-one trillion, five hundred twelve billion, four hundred twenty-one million, three hundred forty-two thousand, four hundred twenty-five".