77781890 has 8 divisors (see below), whose sum is σ = 140007420. Its totient is φ = 31112752.

The previous prime is 77781889. The next prime is 77781923. The reversal of 77781890 is 9818777.

It can be written as a sum of positive squares in 2 ways, for example, as 76020961 + 1760929 = 8719^2 + 1327^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3889085 + ... + 3889104.

Almost surely, 2^77781890 is an apocalyptic number.

77781890 is a deficient number, since it is larger than the sum of its proper divisors (62225530).

77781890 is a wasteful number, since it uses less digits than its factorization.

77781890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7778196.

The product of its (nonzero) digits is 197568, while the sum is 47.

The square root of 77781890 is about 8819.4041748862. The cubic root of 77781890 is about 426.8672444243.

The spelling of 77781890 in words is "seventy-seven million, seven hundred eighty-one thousand, eight hundred ninety".