21530145145 has 8 divisors (see below), whose sum is σ = 25841072520. Its totient is φ = 17220850560.

The previous prime is 21530145073. The next prime is 21530145179. The reversal of 21530145145 is 54154103512.

It can be written as a sum of positive squares in 4 ways, for example, as 1802257209 + 19727887936 = 42453^2 + 140456^2 .

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

It is not a de Polignac number, because 21530145145 - 2¹⁹ = 21529620857 is a prime.

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, 378996 + ... + 432085.

It is an arithmetic number, because the mean of its divisors is an integer number (3230134065).

Almost surely, 2^21530145145 is an apocalyptic number.

It is an amenable number.

21530145145 is a deficient number, since it is larger than the sum of its proper divisors (4310927375).

21530145145 is an equidigital number, since it uses as much as digits as its factorization.

21530145145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 816395.

The product of its (nonzero) digits is 12000, while the sum is 31.

Adding to 21530145145 its reverse (54154103512), we get a palindrome (75684248657).

The spelling of 21530145145 in words is "twenty-one billion, five hundred thirty million, one hundred forty-five thousand, one hundred forty-five".