21425005642 has 16 divisors (see below), whose sum is σ = 33260378760. Its totient is φ = 10338539008.

The previous prime is 21425005639. The next prime is 21425005643. The reversal of 21425005642 is 24650052412.

It can be written as a sum of positive squares in 4 ways, for example, as 21421542321 + 3463321 = 146361^2 + 1861^2 .

It is not an unprimeable number, because it can be changed into a prime (21425005643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 52818 + ... + 213634.

Almost surely, 2^21425005642 is an apocalyptic number.

21425005642 is a deficient number, since it is larger than the sum of its proper divisors (11835373118).

21425005642 is a wasteful number, since it uses less digits than its factorization.

21425005642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 163145.

The product of its (nonzero) digits is 19200, while the sum is 31.

The spelling of 21425005642 in words is "twenty-one billion, four hundred twenty-five million, five thousand, six hundred forty-two".