61397778667 has 4 divisors (see below), whose sum is σ = 61398806976. Its totient is φ = 61396750360.

The previous prime is 61397778661. The next prime is 61397778691. The reversal of 61397778667 is 76687779316.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 61397778667 - 2⁷ = 61397778539 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61397778661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 418684 + ... + 545977.

It is an arithmetic number, because the mean of its divisors is an integer number (15349701744).

Almost surely, 2^61397778667 is an apocalyptic number.

61397778667 is a deficient number, since it is larger than the sum of its proper divisors (1028309).

61397778667 is an equidigital number, since it uses as much as digits as its factorization.

61397778667 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1028308.

The product of its digits is 112021056, while the sum is 67.

The spelling of 61397778667 in words is "sixty-one billion, three hundred ninety-seven million, seven hundred seventy-eight thousand, six hundred sixty-seven".