1620400345 has 8 divisors (see below), whose sum is σ = 1971117576. Its totient is φ = 1278562176.

The previous prime is 1620400337. The next prime is 1620400381. The reversal of 1620400345 is 5430040261.

It can be written as a sum of positive squares in 4 ways, for example, as 748733769 + 871666576 = 27363^2 + 29524^2 .

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 1620400345 - 2³ = 1620400337 is a prime.

It is a super-2 number, since 2×1620400345² = 5251394556152238050, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2219362 + ... + 2220091.

It is an arithmetic number, because the mean of its divisors is an integer number (246389697).

Almost surely, 2^1620400345 is an apocalyptic number.

It is an amenable number.

1620400345 is a deficient number, since it is larger than the sum of its proper divisors (350717231).

1620400345 is an equidigital number, since it uses as much as digits as its factorization.

1620400345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4439531.

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 1620400345 is about 40254.1966135209. The cubic root of 1620400345 is about 1174.5570311529.

The spelling of 1620400345 in words is "one billion, six hundred twenty million, four hundred thousand, three hundred forty-five".