145021561 has 4 divisors (see below), whose sum is σ = 145324800. Its totient is φ = 144718324.

The previous prime is 145021549. The next prime is 145021573. The reversal of 145021561 is 165120541.

It is a happy number.

145021561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (145021549) and next prime (145021573).

It is a cyclic number.

It is not a de Polignac number, because 145021561 - 2¹⁵ = 144988793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (145021511) 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, 150901 + ... + 151858.

It is an arithmetic number, because the mean of its divisors is an integer number (36331200).

Almost surely, 2^145021561 is an apocalyptic number.

It is an amenable number.

145021561 is a deficient number, since it is larger than the sum of its proper divisors (303239).

145021561 is an equidigital number, since it uses as much as digits as its factorization.

145021561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 303238.

The product of its (nonzero) digits is 1200, while the sum is 25.

The square root of 145021561 is about 12042.4898173094. The cubic root of 145021561 is about 525.3848256388.

The spelling of 145021561 in words is "one hundred forty-five million, twenty-one thousand, five hundred sixty-one".