39645661 has 4 divisors (see below), whose sum is σ = 43249824. Its totient is φ = 36041500.

The previous prime is 39645637. The next prime is 39645689. The reversal of 39645661 is 16654693.

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 an emirpimes, since its reverse is a distinct semiprime: 16654693 = 11 ⋅1514063.

It is not a de Polignac number, because 39645661 - 2¹³ = 39637469 is a prime.

It is a super-2 number, since 2×39645661² = 3143556872253842, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (39645601) 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, 1802065 + ... + 1802086.

It is an arithmetic number, because the mean of its divisors is an integer number (10812456).

Almost surely, 2^39645661 is an apocalyptic number.

It is an amenable number.

39645661 is a deficient number, since it is larger than the sum of its proper divisors (3604163).

39645661 is a wasteful number, since it uses less digits than its factorization.

39645661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3604162.

The product of its digits is 116640, while the sum is 40.

The square root of 39645661 is about 6296.4800484080. The cubic root of 39645661 is about 340.9823407120.

The spelling of 39645661 in words is "thirty-nine million, six hundred forty-five thousand, six hundred sixty-one".