11721890 has 16 divisors (see below), whose sum is σ = 21143808. Its totient is φ = 4678896.

The previous prime is 11721889. The next prime is 11721893. The reversal of 11721890 is 9812711.

11721890 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-4 number, since 4×11721890⁴ (a number of 29 digits) contains 4444 as substring.

It is not an unprimeable number, because it can be changed into a prime (11721893) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5519 + ... + 7341.

It is an arithmetic number, because the mean of its divisors is an integer number (1321488).

Almost surely, 2^11721890 is an apocalyptic number.

11721890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

11721890 is a deficient number, since it is larger than the sum of its proper divisors (9421918).

11721890 is a wasteful number, since it uses less digits than its factorization.

11721890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2473.

The product of its (nonzero) digits is 1008, while the sum is 29.

The square root of 11721890 is about 3423.7245800444. The cubic root of 11721890 is about 227.1603594342.

The spelling of 11721890 in words is "eleven million, seven hundred twenty-one thousand, eight hundred ninety".