21121394 has 8 divisors (see below), whose sum is σ = 36208128. Its totient is φ = 9052020.

The previous prime is 21121381. The next prime is 21121403. The reversal of 21121394 is 49312112.

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

It is a super-2 number, since 2×21121394² = 892226569006472, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 754322 + ... + 754349.

It is an arithmetic number, because the mean of its divisors is an integer number (4526016).

Almost surely, 2^21121394 is an apocalyptic number.

21121394 is a deficient number, since it is larger than the sum of its proper divisors (15086734).

21121394 is a wasteful number, since it uses less digits than its factorization.

21121394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1508680.

The product of its digits is 432, while the sum is 23.

The square root of 21121394 is about 4595.8017798856. The cubic root of 21121394 is about 276.4230105881.

The spelling of 21121394 in words is "twenty-one million, one hundred twenty-one thousand, three hundred ninety-four".