21550431405 has 8 divisors (see below), whose sum is σ = 34480690272. Its totient is φ = 11493563408.

The previous prime is 21550431359. The next prime is 21550431433. The reversal of 21550431405 is 50413405512.

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 21550431405 - 2⁶ = 21550431341 is a prime.

It is a super-2 number, since 2×21550431405² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 718347699 + ... + 718347728.

It is an arithmetic number, because the mean of its divisors is an integer number (4310086284).

Almost surely, 2^21550431405 is an apocalyptic number.

It is an amenable number.

21550431405 is a deficient number, since it is larger than the sum of its proper divisors (12930258867).

21550431405 is a wasteful number, since it uses less digits than its factorization.

21550431405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1436695435.

The product of its (nonzero) digits is 12000, while the sum is 30.

Adding to 21550431405 its reverse (50413405512), we get a palindrome (71963836917).

The spelling of 21550431405 in words is "twenty-one billion, five hundred fifty million, four hundred thirty-one thousand, four hundred five".