21937381 has 8 divisors (see below), whose sum is σ = 23223200. Its totient is φ = 20664720.

The previous prime is 21937379. The next prime is 21937387. The reversal of 21937381 is 18373912.

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

It is a cyclic number.

It is not a de Polignac number, because 21937381 - 2¹ = 21937379 is a prime.

It is a super-2 number, since 2×21937381² = 962497370278322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21937387) 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, 250 + ... + 6628.

It is an arithmetic number, because the mean of its divisors is an integer number (2902900).

Almost surely, 2^21937381 is an apocalyptic number.

It is an amenable number.

21937381 is a deficient number, since it is larger than the sum of its proper divisors (1285819).

21937381 is a wasteful number, since it uses less digits than its factorization.

21937381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6579.

The product of its digits is 9072, while the sum is 34.

The square root of 21937381 is about 4683.7357952814. The cubic root of 21937381 is about 279.9378305851.

The spelling of 21937381 in words is "twenty-one million, nine hundred thirty-seven thousand, three hundred eighty-one".