1620400275 has 96 divisors (see below), whose sum is σ = 3374784000. Its totient is φ = 755671680.

The previous prime is 1620400273. The next prime is 1620400321. The reversal of 1620400275 is 5720040261.

It is not a de Polignac number, because 1620400275 - 2¹ = 1620400273 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (1620400273) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 161866 + ... + 171584.

It is an arithmetic number, because the mean of its divisors is an integer number (35154000).

Almost surely, 2^1620400275 is an apocalyptic number.

1620400275 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1620400275 is an abundant number, since it is smaller than the sum of its proper divisors (1754383725).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1620400275 is a wasteful number, since it uses less digits than its factorization.

1620400275 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9770 (or 9759 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

The square root of 1620400275 is about 40254.1957440464. The cubic root of 1620400275 is about 1174.5570142396.

The spelling of 1620400275 in words is "one billion, six hundred twenty million, four hundred thousand, two hundred seventy-five".