1238778761 has 24 divisors (see below), whose sum is σ = 1413417600. Its totient is φ = 1083605600.

The previous prime is 1238778757. The next prime is 1238778767. The reversal of 1238778761 is 1678778321.

It is a happy number.

It is not a de Polignac number, because 1238778761 - 2² = 1238778757 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1238778767) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1722560 + ... + 1723278.

It is an arithmetic number, because the mean of its divisors is an integer number (58892400).

Almost surely, 2^1238778761 is an apocalyptic number.

1238778761 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1238778761 is a deficient number, since it is larger than the sum of its proper divisors (174638839).

1238778761 is a wasteful number, since it uses less digits than its factorization.

1238778761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1261 (or 1250 counting only the distinct ones).

The product of its digits is 790272, while the sum is 50.

The square root of 1238778761 is about 35196.2890231342. The cubic root of 1238778761 is about 1073.9842609648.

The spelling of 1238778761 in words is "one billion, two hundred thirty-eight million, seven hundred seventy-eight thousand, seven hundred sixty-one".