21150381 has 8 divisors (see below), whose sum is σ = 32229184. Its totient is φ = 12085920.

The previous prime is 21150377. The next prime is 21150407. The reversal of 21150381 is 18305112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21150381 - 2² = 21150377 is a prime.

It is a super-2 number, since 2×21150381² = 894677232890322, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21), and also a Moran number because the ratio is a prime number: 1007161 = 21150381 / (2 + 1 + 1 + 5 + 0 + 3 + 8 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21150331) 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 7 ways as a sum of consecutive naturals, for example, 503560 + ... + 503601.

It is an arithmetic number, because the mean of its divisors is an integer number (4028648).

Almost surely, 2^21150381 is an apocalyptic number.

21150381 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21150381 is a deficient number, since it is larger than the sum of its proper divisors (11078803).

21150381 is a wasteful number, since it uses less digits than its factorization.

21150381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1007171.

The product of its (nonzero) digits is 240, while the sum is 21.

The square root of 21150381 is about 4598.9543376729. The cubic root of 21150381 is about 276.5494070919.

Adding to 21150381 its reverse (18305112), we get a palindrome (39455493).

The spelling of 21150381 in words is "twenty-one million, one hundred fifty thousand, three hundred eighty-one".