661464877 has 2 divisors, whose sum is σ = 661464878. Its totient is φ = 661464876.

The previous prime is 661464833. The next prime is 661464929. The reversal of 661464877 is 778464166.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 469198921 + 192265956 = 21661^2 + 13866^2 .

It is a cyclic number.

It is not a de Polignac number, because 661464877 - 2¹¹ = 661462829 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 661464877.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661464977) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330732438 + 330732439.

It is an arithmetic number, because the mean of its divisors is an integer number (330732439).

Almost surely, 2^661464877 is an apocalyptic number.

It is an amenable number.

661464877 is a deficient number, since it is larger than the sum of its proper divisors (1).

661464877 is an equidigital number, since it uses as much as digits as its factorization.

661464877 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1354752, while the sum is 49.

The square root of 661464877 is about 25718.9594851736. The cubic root of 661464877 is about 871.3024385990.

The spelling of 661464877 in words is "six hundred sixty-one million, four hundred sixty-four thousand, eight hundred seventy-seven".