1620386145281 has 4 divisors (see below), whose sum is σ = 1636429572564. Its totient is φ = 1604342718000.

The previous prime is 1620386145277. The next prime is 1620386145293. The reversal of 1620386145281 is 1825416830261.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1587247219600 + 33138925681 = 1259860^2 + 182041^2 .

It is a cyclic number.

It is not a de Polignac number, because 1620386145281 - 2² = 1620386145277 is a prime.

It is a super-2 number, since 2×1620386145281² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1620386145881) 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, 8021713490 + ... + 8021713691.

It is an arithmetic number, because the mean of its divisors is an integer number (409107393141).

Almost surely, 2^{1620386145281} is an apocalyptic number.

It is an amenable number.

1620386145281 is a deficient number, since it is larger than the sum of its proper divisors (16043427283).

1620386145281 is a wasteful number, since it uses less digits than its factorization.

1620386145281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16043427282.

The product of its (nonzero) digits is 552960, while the sum is 47.

The spelling of 1620386145281 in words is "one trillion, six hundred twenty billion, three hundred eighty-six million, one hundred forty-five thousand, two hundred eighty-one".