619981 has 2 divisors, whose sum is σ = 619982. Its totient is φ = 619980.

The previous prime is 619979. The next prime is 619987. The reversal of 619981 is 189916.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 538756 + 81225 = 734^2 + 285^2 .

It is a cyclic number.

It is not a de Polignac number, because 619981 - 2¹ = 619979 is a prime.

It is a super-2 number, since 2×619981² = 768752880722, which contains 22 as substring.

Together with 619979, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (619987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 309990 + 309991.

It is an arithmetic number, because the mean of its divisors is an integer number (309991).

2⁶¹⁹⁹⁸¹ is an apocalyptic number.

It is an amenable number.

619981 is a deficient number, since it is larger than the sum of its proper divisors (1).

619981 is an equidigital number, since it uses as much as digits as its factorization.

619981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3888, while the sum is 34.

The square root of 619981 is about 787.3887222967. The cubic root of 619981 is about 85.2693187843.

It can be divided in two parts, 619 and 981, that added together give a square (1600 = 40²).

The spelling of 619981 in words is "six hundred nineteen thousand, nine hundred eighty-one".