145916621 has 4 divisors (see below), whose sum is σ = 145945500. Its totient is φ = 145887744.

The previous prime is 145916569. The next prime is 145916647. The reversal of 145916621 is 126619541.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 17547721 + 128368900 = 4189^2 + 11330^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-145916621 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (145916671) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4646 + ... + 17703.

It is an arithmetic number, because the mean of its divisors is an integer number (36486375).

Almost surely, 2^145916621 is an apocalyptic number.

It is an amenable number.

145916621 is a deficient number, since it is larger than the sum of its proper divisors (28879).

145916621 is an equidigital number, since it uses as much as digits as its factorization.

145916621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28878.

The product of its digits is 12960, while the sum is 35.

The square root of 145916621 is about 12079.5952332849. The cubic root of 145916621 is about 526.4634854684.

It can be divided in two parts, 14591 and 6621, that added together give a palindrome (21212).

The spelling of 145916621 in words is "one hundred forty-five million, nine hundred sixteen thousand, six hundred twenty-one".