21000145306 has 24 divisors (see below), whose sum is σ = 37536852276. Its totient is φ = 8780546880.

The previous prime is 21000145273. The next prime is 21000145337. The reversal of 21000145306 is 60354100012.

It can be written as a sum of positive squares in 2 ways, for example, as 20702893225 + 297252081 = 143885^2 + 17241^2 .

It is a super-2 number, since 2×21000145306² (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 11 ways as a sum of consecutive naturals, for example, 2609241 + ... + 2617276.

Almost surely, 2^21000145306 is an apocalyptic number.

21000145306 is a deficient number, since it is larger than the sum of its proper divisors (16536706970).

21000145306 is a wasteful number, since it uses less digits than its factorization.

21000145306 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5226574 (or 5226567 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 22.

Adding to 21000145306 its reverse (60354100012), we get a palindrome (81354245318).

The spelling of 21000145306 in words is "twenty-one billion, one hundred forty-five thousand, three hundred six".