9919785655 has 16 divisors (see below), whose sum is σ = 13165889184. Its totient is φ = 7127395200.

The previous prime is 9919785647. The next prime is 9919785721. The reversal of 9919785655 is 5565879199.

It is not a de Polignac number, because 9919785655 - 2³ = 9919785647 is a prime.

It is a super-2 number, since 2×9919785655² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2059921 + ... + 2064730.

It is an arithmetic number, because the mean of its divisors is an integer number (822868074).

Almost surely, 2^9919785655 is an apocalyptic number.

9919785655 is a deficient number, since it is larger than the sum of its proper divisors (3246103529).

9919785655 is a wasteful number, since it uses less digits than its factorization.

9919785655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4124706.

The product of its digits is 30618000, while the sum is 64.

The square root of 9919785655 is about 99598.1207403031. The cubic root of 9919785655 is about 2148.6586661420.

The spelling of 9919785655 in words is "nine billion, nine hundred nineteen million, seven hundred eighty-five thousand, six hundred fifty-five".