1217251920 has 40 divisors (see below), whose sum is σ = 3773481696. Its totient is φ = 324600448.

The previous prime is 1217251897. The next prime is 1217251939. The reversal of 1217251920 is 291527121.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2535702 + ... + 2536181.

Almost surely, 2^1217251920 is an apocalyptic number.

1217251920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1217251920 is an abundant number, since it is smaller than the sum of its proper divisors (2556229776).

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

1217251920 is a wasteful number, since it uses less digits than its factorization.

1217251920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5071899 (or 5071893 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 30.

The square root of 1217251920 is about 34889.1375645773. The cubic root of 1217251920 is about 1067.7268304989.

The spelling of 1217251920 in words is "one billion, two hundred seventeen million, two hundred fifty-one thousand, nine hundred twenty".