4001905661 has 8 divisors (see below), whose sum is σ = 4448769024. Its totient is φ = 3574902960.

The previous prime is 4001905657. The next prime is 4001905727. The reversal of 4001905661 is 1665091004.

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 4001905661 - 2² = 4001905657 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 (4001905651) 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, 4964741 + ... + 4965546.

It is an arithmetic number, because the mean of its divisors is an integer number (556096128).

Almost surely, 2^4001905661 is an apocalyptic number.

It is an amenable number.

4001905661 is a deficient number, since it is larger than the sum of its proper divisors (446863363).

4001905661 is a wasteful number, since it uses less digits than its factorization.

4001905661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9930331.

The product of its (nonzero) digits is 6480, while the sum is 32.

The square root of 4001905661 is about 63260.6169824481. The cubic root of 4001905661 is about 1587.6530993024.

Adding to 4001905661 its reverse (1665091004), we get a palindrome (5666996665).

The spelling of 4001905661 in words is "four billion, one million, nine hundred five thousand, six hundred sixty-one".