21000145 has 8 divisors (see below), whose sum is σ = 25576704. Its totient is φ = 16549104.

The previous prime is 21000143. The next prime is 21000157. The reversal of 21000145 is 54100012.

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 21000145 - 2¹ = 21000143 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21000143) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31009 + ... + 31678.

It is an arithmetic number, because the mean of its divisors is an integer number (3197088).

Almost surely, 2^21000145 is an apocalyptic number.

It is an amenable number.

21000145 is a deficient number, since it is larger than the sum of its proper divisors (4576559).

21000145 is an equidigital number, since it uses as much as digits as its factorization.

21000145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62759.

The product of its (nonzero) digits is 40, while the sum is 13.

The square root of 21000145 is about 4582.5915157256. The cubic root of 21000145 is about 275.8930526271.

Adding to 21000145 its reverse (54100012), we get a palindrome (75100157).

The spelling of 21000145 in words is "twenty-one million, one hundred forty-five", and thus it is an aban number.