1620401321 has 16 divisors (see below), whose sum is σ = 2022263808. Its totient is φ = 1261386000.

The previous prime is 1620401317. The next prime is 1620401323. The reversal of 1620401321 is 1231040261.

It is not a de Polignac number, because 1620401321 - 2² = 1620401317 is a prime.

It is a super-5 number, since 5×1620401321⁵ (a number of 47 digits) contains 55555 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1620401293 and 1620401302.

It is not an unprimeable number, because it can be changed into a prime (1620401323) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 70916 + ... + 90938.

It is an arithmetic number, because the mean of its divisors is an integer number (126391488).

Almost surely, 2^1620401321 is an apocalyptic number.

1620401321 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1620401321 is a deficient number, since it is larger than the sum of its proper divisors (401862487).

1620401321 is a wasteful number, since it uses less digits than its factorization.

1620401321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21092.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 1620401321 is about 40254.2087364787. The cubic root of 1620401321 is about 1174.5572669727.

Adding to 1620401321 its reverse (1231040261), we get a palindrome (2851441582).

It can be divided in two parts, 162040 and 1321, that added together give a palindrome (163361).

The spelling of 1620401321 in words is "one billion, six hundred twenty million, four hundred one thousand, three hundred twenty-one".