21531351030421 has 8 divisors (see below), whose sum is σ = 23353947459864. Its totient is φ = 19770537530880.

The previous prime is 21531351030383. The next prime is 21531351030451. The reversal of 21531351030421 is 12403015313512.

It can be written as a sum of positive squares in 4 ways, for example, as 54744300625 + 21476606729796 = 233975^2 + 4634286^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21531351030421 - 2¹¹ = 21531351028373 is a prime.

It is a super-2 number, since 2×21531351030421² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21531351030451) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15445731750 + ... + 15445733143.

It is an arithmetic number, because the mean of its divisors is an integer number (2919243432483).

Almost surely, 2^{21531351030421} is an apocalyptic number.

It is an amenable number.

21531351030421 is a deficient number, since it is larger than the sum of its proper divisors (1822596429443).

21531351030421 is a wasteful number, since it uses less digits than its factorization.

21531351030421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30891464951.

The product of its (nonzero) digits is 10800, while the sum is 31.

Adding to 21531351030421 its reverse (12403015313512), we get a palindrome (33934366343933).

The spelling of 21531351030421 in words is "twenty-one trillion, five hundred thirty-one billion, three hundred fifty-one million, thirty thousand, four hundred twenty-one".