145721609 has 8 divisors (see below), whose sum is σ = 159431328. Its totient is φ = 132088960.

The previous prime is 145721599. The next prime is 145721617. The reversal of 145721609 is 906127541.

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 145721609 - 2⁴ = 145721593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (145721699) 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, 15272 + ... + 22905.

It is an arithmetic number, because the mean of its divisors is an integer number (19928916).

Almost surely, 2^145721609 is an apocalyptic number.

It is an amenable number.

145721609 is a deficient number, since it is larger than the sum of its proper divisors (13709719).

145721609 is a wasteful number, since it uses less digits than its factorization.

145721609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38535.

The product of its (nonzero) digits is 15120, while the sum is 35.

The square root of 145721609 is about 12071.5205753045. The cubic root of 145721609 is about 526.2288481182.

The spelling of 145721609 in words is "one hundred forty-five million, seven hundred twenty-one thousand, six hundred nine".