661645145 has 32 divisors (see below), whose sum is σ = 923320320. Its totient is φ = 445798080.

The previous prime is 661645123. The next prime is 661645147. The reversal of 661645145 is 541546166.

It is a happy number.

It is not a de Polignac number, because 661645145 - 2¹⁰ = 661644121 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 661645099 and 661645108.

It is not an unprimeable number, because it can be changed into a prime (661645147) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 748874 + ... + 749756.

It is an arithmetic number, because the mean of its divisors is an integer number (28853760).

Almost surely, 2^661645145 is an apocalyptic number.

It is an amenable number.

661645145 is a deficient number, since it is larger than the sum of its proper divisors (261675175).

661645145 is a wasteful number, since it uses less digits than its factorization.

661645145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1245.

The product of its digits is 86400, while the sum is 38.

The square root of 661645145 is about 25722.4638205596. The cubic root of 661645145 is about 871.3815829785.

The spelling of 661645145 in words is "six hundred sixty-one million, six hundred forty-five thousand, one hundred forty-five".