21000145305 has 64 divisors (see below), whose sum is σ = 35859898368. Its totient is φ = 10457717760.

The previous prime is 21000145273. The next prime is 21000145337. The reversal of 21000145305 is 50354100012.

It is an interprime number because it is at equal distance from previous prime (21000145273) and next prime (21000145337).

It is not a de Polignac number, because 21000145305 - 2⁵ = 21000145273 is a prime.

It is a super-2 number, since 2×21000145305² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 32659314 + ... + 32659956.

It is an arithmetic number, because the mean of its divisors is an integer number (560310912).

Almost surely, 2^21000145305 is an apocalyptic number.

It is an amenable number.

21000145305 is a deficient number, since it is larger than the sum of its proper divisors (14859753063).

21000145305 is a wasteful number, since it uses less digits than its factorization.

21000145305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1486.

The product of its (nonzero) digits is 600, while the sum is 21.

Adding to 21000145305 its reverse (50354100012), we get a palindrome (71354245317).

The spelling of 21000145305 in words is "twenty-one billion, one hundred forty-five thousand, three hundred five".