61491779 has 2 divisors, whose sum is σ = 61491780. Its totient is φ = 61491778.

The previous prime is 61491757. The next prime is 61491823. The reversal of 61491779 is 97719416.

It is an a-pointer prime, because the next prime (61491823) can be obtained adding 61491779 to its sum of digits (44).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 61491779 - 2¹⁶ = 61426243 is a prime.

It is not a weakly prime, because it can be changed into another prime (61491709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30745889 + 30745890.

It is an arithmetic number, because the mean of its divisors is an integer number (30745890).

Almost surely, 2^61491779 is an apocalyptic number.

61491779 is a deficient number, since it is larger than the sum of its proper divisors (1).

61491779 is an equidigital number, since it uses as much as digits as its factorization.

61491779 is an evil number, because the sum of its binary digits is even.

The product of its digits is 95256, while the sum is 44.

The square root of 61491779 is about 7841.6694013456. The cubic root of 61491779 is about 394.7047497219.

The spelling of 61491779 in words is "sixty-one million, four hundred ninety-one thousand, seven hundred seventy-nine".