1265992890 has 32 divisors (see below), whose sum is σ = 3217112640. Its totient is φ = 317739264.

The previous prime is 1265992877. The next prime is 1265992891. The reversal of 1265992890 is 982995621.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is not an unprimeable number, because it can be changed into a prime (1265992891) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1240660 + ... + 1241679.

It is an arithmetic number, because the mean of its divisors is an integer number (100534770).

Almost surely, 2^1265992890 is an apocalyptic number.

1265992890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1265992890 is an abundant number, since it is smaller than the sum of its proper divisors (1951119750).

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

1265992890 is a wasteful number, since it uses less digits than its factorization.

1265992890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2482366.

The product of its (nonzero) digits is 699840, while the sum is 51.

The square root of 1265992890 is about 35580.7938360009. The cubic root of 1265992890 is about 1081.7919753192.

The spelling of 1265992890 in words is "one billion, two hundred sixty-five million, nine hundred ninety-two thousand, eight hundred ninety".