21015250421 has 8 divisors (see below), whose sum is σ = 22936521600. Its totient is φ = 19095778240.

The previous prime is 21015250411. The next prime is 21015250457. The reversal of 21015250421 is 12405251012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21015250421 - 2⁶ = 21015250357 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21015250411) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 425261 + ... + 472098.

It is an arithmetic number, because the mean of its divisors is an integer number (2867065200).

Almost surely, 2^21015250421 is an apocalyptic number.

It is an amenable number.

21015250421 is a deficient number, since it is larger than the sum of its proper divisors (1921271179).

21015250421 is a wasteful number, since it uses less digits than its factorization.

21015250421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 899499.

The product of its (nonzero) digits is 800, while the sum is 23.

The spelling of 21015250421 in words is "twenty-one billion, fifteen million, two hundred fifty thousand, four hundred twenty-one".