11897820 has 96 divisors (see below), whose sum is σ = 40400640. Its totient is φ = 2882880.

The previous prime is 11897803. The next prime is 11897827. The reversal of 11897820 is 2879811.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11897827) 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, 4939 + ... + 6941.

It is an arithmetic number, because the mean of its divisors is an integer number (420840).

Almost surely, 2^11897820 is an apocalyptic number.

11897820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 11897820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20200320).

11897820 is an abundant number, since it is smaller than the sum of its proper divisors (28502820).

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

11897820 is a wasteful number, since it uses less digits than its factorization.

11897820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2032 (or 2024 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 36.

The square root of 11897820 is about 3449.3216724452. The cubic root of 11897820 is about 228.2911792227.

Subtracting from 11897820 its reverse (2879811), we obtain a square (9018009 = 3003²).

It can be divided in two parts, 1189 and 7820, that added together give a palindrome (9009).

The spelling of 11897820 in words is "eleven million, eight hundred ninety-seven thousand, eight hundred twenty".