21167890 has 32 divisors (see below), whose sum is σ = 41341104. Its totient is φ = 7772160.

The previous prime is 21167863. The next prime is 21167891. The reversal of 21167890 is 9876112.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 10297681 + 10870209 = 3209^2 + 3297^2 .

It is a Harshad number since it is a multiple of its sum of digits (34).

It is not an unprimeable number, because it can be changed into a prime (21167891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5452 + ... + 8488.

Almost surely, 2^21167890 is an apocalyptic number.

21167890 is a deficient number, since it is larger than the sum of its proper divisors (20173214).

21167890 is a wasteful number, since it uses less digits than its factorization.

21167890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3102.

The product of its (nonzero) digits is 6048, while the sum is 34.

The square root of 21167890 is about 4600.8575287657. The cubic root of 21167890 is about 276.6256983579.

The spelling of 21167890 in words is "twenty-one million, one hundred sixty-seven thousand, eight hundred ninety".