1616001581 has 2 divisors, whose sum is σ = 1616001582. Its totient is φ = 1616001580.

The previous prime is 1616001577. The next prime is 1616001631. The reversal of 1616001581 is 1851006161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1266648100 + 349353481 = 35590^2 + 18691^2 .

It is a cyclic number.

It is not a de Polignac number, because 1616001581 - 2² = 1616001577 is a prime.

It is a super-2 number, since 2×1616001581² = 5222922219588999122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1616001571) 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 as a sum of consecutive naturals, namely, 808000790 + 808000791.

It is an arithmetic number, because the mean of its divisors is an integer number (808000791).

Almost surely, 2^1616001581 is an apocalyptic number.

It is an amenable number.

1616001581 is a deficient number, since it is larger than the sum of its proper divisors (1).

1616001581 is an equidigital number, since it uses as much as digits as its factorization.

1616001581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1440, while the sum is 29.

The square root of 1616001581 is about 40199.5221489012. The cubic root of 1616001581 is about 1173.4932443807.

The spelling of 1616001581 in words is "one billion, six hundred sixteen million, one thousand, five hundred eighty-one".