611666551 has 2 divisors, whose sum is σ = 611666552. Its totient is φ = 611666550.

The previous prime is 611666537. The next prime is 611666599. The reversal of 611666551 is 155666116.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 611666551 - 2¹⁵ = 611633783 is a prime.

It is a super-2 number, since 2×611666551² = 748271939224471202, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 611666551.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (611696551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 305833275 + 305833276.

It is an arithmetic number, because the mean of its divisors is an integer number (305833276).

Almost surely, 2^611666551 is an apocalyptic number.

611666551 is a deficient number, since it is larger than the sum of its proper divisors (1).

611666551 is an equidigital number, since it uses as much as digits as its factorization.

611666551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32400, while the sum is 37.

The square root of 611666551 is about 24731.8933969884. The cubic root of 611666551 is about 848.8642505891.

The spelling of 611666551 in words is "six hundred eleven million, six hundred sixty-six thousand, five hundred fifty-one".