21149040 has 80 divisors (see below), whose sum is σ = 71531136. Its totient is φ = 5126400.

The previous prime is 21149039. The next prime is 21149041. The reversal of 21149040 is 4094112.

It is an interprime number because it is at equal distance from previous prime (21149039) and next prime (21149041).

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 21148998 and 21149016.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21149041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1366 + ... + 6645.

Almost surely, 2^21149040 is an apocalyptic number.

21149040 is a gapful number since it is divisible by the number (20) 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 21149040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35765568).

21149040 is an abundant number, since it is smaller than the sum of its proper divisors (50382096).

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

21149040 is a wasteful number, since it uses less digits than its factorization.

21149040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8038 (or 8032 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 21149040 is about 4598.8085413507. The cubic root of 21149040 is about 276.5435622706.

The spelling of 21149040 in words is "twenty-one million, one hundred forty-nine thousand, forty".