1606406401 has 4 divisors (see below), whose sum is σ = 1610412804. Its totient is φ = 1602400000.

The previous prime is 1606406383. The next prime is 1606406419. The reversal of 1606406401 is 1046046061.

It is a Cunningham number, because it is equal to 40080²+1.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1046046061 = 103 ⋅10155787.

It is an interprime number because it is at equal distance from previous prime (1606406383) and next prime (1606406419).

It can be written as a sum of positive squares in 2 ways, for example, as 1590414400 + 15992001 = 39880^2 + 3999^2 .

It is a cyclic number.

It is not a de Polignac number, because 1606406401 - 2⁵ = 1606406369 is a prime.

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 1606406401.

It is not an unprimeable number, because it can be changed into a prime (1606406441) 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, 2002600 + ... + 2003401.

It is an arithmetic number, because the mean of its divisors is an integer number (402603201).

Almost surely, 2^1606406401 is an apocalyptic number.

It is an amenable number.

1606406401 is a deficient number, since it is larger than the sum of its proper divisors (4006403).

1606406401 is an equidigital number, since it uses as much as digits as its factorization.

1606406401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4006402.

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 1606406401 is about 40080.0000124750. Note that the first 4 decimals coincide. The cubic root of 1606406401 is about 1171.1660522914.

The spelling of 1606406401 in words is "one billion, six hundred six million, four hundred six thousand, four hundred one".