61666727898 has 16 divisors (see below), whose sum is σ = 123849498240. Its totient is φ = 20469568896.

The previous prime is 61666727879. The next prime is 61666727917. The reversal of 61666727898 is 89872766616.

It is an interprime number because it is at equal distance from previous prime (61666727879) and next prime (61666727917).

It is a super-3 number, since 3×61666727898³ (a number of 33 digits) contains 333 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21500215 + ... + 21503082.

It is an arithmetic number, because the mean of its divisors is an integer number (7740593640).

Almost surely, 2^61666727898 is an apocalyptic number.

61666727898 is an abundant number, since it is smaller than the sum of its proper divisors (62182770342).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

61666727898 is a wasteful number, since it uses less digits than its factorization.

61666727898 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43003541.

The product of its digits is 73156608, while the sum is 66.

The spelling of 61666727898 in words is "sixty-one billion, six hundred sixty-six million, seven hundred twenty-seven thousand, eight hundred ninety-eight".