61257771979 has 2 divisors, whose sum is σ = 61257771980. Its totient is φ = 61257771978.

The previous prime is 61257771973. The next prime is 61257772003. The reversal of 61257771979 is 97917775216.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 61257771979 - 2⁷ = 61257771851 is a prime.

It is not a weakly prime, because it can be changed into another prime (61257771973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30628885989 + 30628885990.

It is an arithmetic number, because the mean of its divisors is an integer number (30628885990).

Almost surely, 2^61257771979 is an apocalyptic number.

61257771979 is a deficient number, since it is larger than the sum of its proper divisors (1).

61257771979 is an equidigital number, since it uses as much as digits as its factorization.

61257771979 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11668860, while the sum is 61.

The spelling of 61257771979 in words is "sixty-one billion, two hundred fifty-seven million, seven hundred seventy-one thousand, nine hundred seventy-nine".