1612990781 has 2 divisors, whose sum is σ = 1612990782. Its totient is φ = 1612990780.

The previous prime is 1612990777. The next prime is 1612990811. The reversal of 1612990781 is 1870992161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1067067556 + 545923225 = 32666^2 + 23365^2 .

It is an emirp because it is prime and its reverse (1870992161) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1612990781 - 2² = 1612990777 is a prime.

It is a super-2 number, since 2×1612990781² = 5203478519181979922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1612990751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 806495390 + 806495391.

It is an arithmetic number, because the mean of its divisors is an integer number (806495391).

Almost surely, 2^1612990781 is an apocalyptic number.

It is an amenable number.

1612990781 is a deficient number, since it is larger than the sum of its proper divisors (1).

1612990781 is an equidigital number, since it uses as much as digits as its factorization.

1612990781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 54432, while the sum is 44.

The square root of 1612990781 is about 40162.0564837011. The cubic root of 1612990781 is about 1172.7640062409.

The spelling of 1612990781 in words is "one billion, six hundred twelve million, nine hundred ninety thousand, seven hundred eighty-one".