21450145505 has 16 divisors (see below), whose sum is σ = 27257841360. Its totient is φ = 16148600832.

The previous prime is 21450145447. The next prime is 21450145511. The reversal of 21450145505 is 50554105412.

It can be written as a sum of positive squares in 8 ways, for example, as 441672256 + 21008473249 = 21016^2 + 144943^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21450145505 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1041851 + ... + 1062239.

It is an arithmetic number, because the mean of its divisors is an integer number (1703615085).

Almost surely, 2^21450145505 is an apocalyptic number.

It is an amenable number.

21450145505 is a deficient number, since it is larger than the sum of its proper divisors (5807695855).

21450145505 is a wasteful number, since it uses less digits than its factorization.

21450145505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32788.

The product of its (nonzero) digits is 20000, while the sum is 32.

The spelling of 21450145505 in words is "twenty-one billion, four hundred fifty million, one hundred forty-five thousand, five hundred five".