1620852581 has 2 divisors, whose sum is σ = 1620852582. Its totient is φ = 1620852580.

The previous prime is 1620852557. The next prime is 1620852671. The reversal of 1620852581 is 1852580261.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 995402500 + 625450081 = 31550^2 + 25009^2 .

It is a cyclic number.

It is not a de Polignac number, because 1620852581 - 2²⁶ = 1553743717 is a prime.

It is a super-2 number, since 2×1620852581² = 5254326178668723122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1620852511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810426290 + 810426291.

It is an arithmetic number, because the mean of its divisors is an integer number (810426291).

Almost surely, 2^1620852581 is an apocalyptic number.

It is an amenable number.

1620852581 is a deficient number, since it is larger than the sum of its proper divisors (1).

1620852581 is an equidigital number, since it uses as much as digits as its factorization.

1620852581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 38400, while the sum is 38.

The square root of 1620852581 is about 40259.8134744810. The cubic root of 1620852581 is about 1174.6662896596. Note that the first 3 decimals are identical.

The spelling of 1620852581 in words is "one billion, six hundred twenty million, eight hundred fifty-two thousand, five hundred eighty-one".