145709621 has 4 divisors (see below), whose sum is σ = 145734144. Its totient is φ = 145685100.

The previous prime is 145709611. The next prime is 145709639. The reversal of 145709621 is 126907541.

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, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 126907541 = 1237 ⋅102593.

It is a cyclic number.

It is not a de Polignac number, because 145709621 - 2¹⁰ = 145708597 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 (145709611) 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, 2906 + ... + 17316.

It is an arithmetic number, because the mean of its divisors is an integer number (36433536).

Almost surely, 2^145709621 is an apocalyptic number.

It is an amenable number.

145709621 is a deficient number, since it is larger than the sum of its proper divisors (24523).

145709621 is a wasteful number, since it uses less digits than its factorization.

145709621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24522.

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

The square root of 145709621 is about 12071.0240244977. The cubic root of 145709621 is about 526.2144173954.

The spelling of 145709621 in words is "one hundred forty-five million, seven hundred nine thousand, six hundred twenty-one".