1061656781 has 2 divisors, whose sum is σ = 1061656782. Its totient is φ = 1061656780.

The previous prime is 1061656691. The next prime is 1061656819. The reversal of 1061656781 is 1876561601.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1058200900 + 3455881 = 32530^2 + 1859^2 .

It is an emirp because it is prime and its reverse (1876561601) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1061656781 - 2¹⁴ = 1061640397 is a prime.

It is a super-2 number, since 2×1061656781² = 2254230241286563922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1061656081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 530828390 + 530828391.

It is an arithmetic number, because the mean of its divisors is an integer number (530828391).

Almost surely, 2^1061656781 is an apocalyptic number.

It is an amenable number.

1061656781 is a deficient number, since it is larger than the sum of its proper divisors (1).

1061656781 is an equidigital number, since it uses as much as digits as its factorization.

1061656781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 60480, while the sum is 41.

The square root of 1061656781 is about 32583.0750697352. The cubic root of 1061656781 is about 1020.1437644983.

The spelling of 1061656781 in words is "one billion, sixty-one million, six hundred fifty-six thousand, seven hundred eighty-one".