2778238761 has 32 divisors (see below), whose sum is σ = 3911846400. Its totient is φ = 1751915520.

The previous prime is 2778238759. The next prime is 2778238769. The reversal of 2778238761 is 1678328772.

It is a happy number.

It is not a de Polignac number, because 2778238761 - 2¹ = 2778238759 is a prime.

It is a super-2 number, since 2×2778238761² = 15437221226245630242, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (2778238769) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 627925 + ... + 632333.

It is an arithmetic number, because the mean of its divisors is an integer number (122245200).

Almost surely, 2^2778238761 is an apocalyptic number.

It is an amenable number.

2778238761 is a deficient number, since it is larger than the sum of its proper divisors (1133607639).

2778238761 is a wasteful number, since it uses less digits than its factorization.

2778238761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4609.

The product of its digits is 1580544, while the sum is 51.

The square root of 2778238761 is about 52709.0007588837. Note that the first 3 decimals coincide. The cubic root of 2778238761 is about 1405.7988661966.

The spelling of 2778238761 in words is "two billion, seven hundred seventy-eight million, two hundred thirty-eight thousand, seven hundred sixty-one".