620692781 has 2 divisors, whose sum is σ = 620692782. Its totient is φ = 620692780.

The previous prime is 620692777. The next prime is 620692783. The reversal of 620692781 is 187296026.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 521391556 + 99301225 = 22834^2 + 9965^2 .

It is a cyclic number.

It is not a de Polignac number, because 620692781 - 2² = 620692777 is a prime.

It is a super-2 number, since 2×620692781² = 770519056771027922, which contains 22 as substring.

Together with 620692783, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (620692783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310346390 + 310346391.

It is an arithmetic number, because the mean of its divisors is an integer number (310346391).

Almost surely, 2^620692781 is an apocalyptic number.

It is an amenable number.

620692781 is a deficient number, since it is larger than the sum of its proper divisors (1).

620692781 is an equidigital number, since it uses as much as digits as its factorization.

620692781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72576, while the sum is 41.

The square root of 620692781 is about 24913.7066892905. The cubic root of 620692781 is about 853.0193799320.

The spelling of 620692781 in words is "six hundred twenty million, six hundred ninety-two thousand, seven hundred eighty-one".