1605123901 has 8 divisors (see below), whose sum is σ = 1701653184. Its totient is φ = 1508829120.

The previous prime is 1605123887. The next prime is 1605123907. The reversal of 1605123901 is 1093215061.

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 1605123901 - 2²⁵ = 1571569469 is a prime.

It is a super-2 number, since 2×1605123901² = 5152845475122915602, which contains 22 as substring.

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 1605123901.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1605123907) 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, 44425 + ... + 71998.

It is an arithmetic number, because the mean of its divisors is an integer number (212706648).

Almost surely, 2^1605123901 is an apocalyptic number.

It is an amenable number.

1605123901 is a deficient number, since it is larger than the sum of its proper divisors (96529283).

1605123901 is a wasteful number, since it uses less digits than its factorization.

1605123901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117251.

The product of its (nonzero) digits is 1620, while the sum is 28.

The square root of 1605123901 is about 40063.9975663937. The cubic root of 1605123901 is about 1170.8542963208.

Adding to 1605123901 its reverse (1093215061), we get a palindrome (2698338962).

The spelling of 1605123901 in words is "one billion, six hundred five million, one hundred twenty-three thousand, nine hundred one".