145170721 has 8 divisors (see below), whose sum is σ = 149274944. Its totient is φ = 141076080.

The previous prime is 145170719. The next prime is 145170749. The reversal of 145170721 is 127071541.

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 145170721 - 2¹ = 145170719 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 145170721.

It is not an unprimeable number, because it can be changed into a prime (145170121) 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, 37486 + ... + 41176.

It is an arithmetic number, because the mean of its divisors is an integer number (18659368).

Almost surely, 2^145170721 is an apocalyptic number.

It is an amenable number.

145170721 is a deficient number, since it is larger than the sum of its proper divisors (4104223).

145170721 is a wasteful number, since it uses less digits than its factorization.

145170721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4791.

The product of its (nonzero) digits is 1960, while the sum is 28.

The square root of 145170721 is about 12048.6812971379. The cubic root of 145170721 is about 525.5648897796.

The spelling of 145170721 in words is "one hundred forty-five million, one hundred seventy thousand, seven hundred twenty-one".