101561778 has 12 divisors (see below), whose sum is σ = 220050558. Its totient is φ = 33853920.

The previous prime is 101561771. The next prime is 101561807. The reversal of 101561778 is 877165101.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 69105969 + 32455809 = 8313^2 + 5697^2 .

It is not an unprimeable number, because it can be changed into a prime (101561771) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2821143 + ... + 2821178.

Almost surely, 2^101561778 is an apocalyptic number.

101561778 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

101561778 is an abundant number, since it is smaller than the sum of its proper divisors (118488780).

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

101561778 is a wasteful number, since it uses less digits than its factorization.

101561778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5642329 (or 5642326 counting only the distinct ones).

The product of its (nonzero) digits is 11760, while the sum is 36.

The square root of 101561778 is about 10077.7863640782. The cubic root of 101561778 is about 466.5627890106.

The spelling of 101561778 in words is "one hundred one million, five hundred sixty-one thousand, seven hundred seventy-eight".