21047351 has 8 divisors (see below), whose sum is σ = 22901424. Its totient is φ = 19226880.

The previous prime is 21047333. The next prime is 21047363. The reversal of 21047351 is 15374012.

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 21047351 - 2¹⁰ = 21046327 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21047371) 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, 7085 + ... + 9606.

It is an arithmetic number, because the mean of its divisors is an integer number (2862678).

Almost surely, 2^21047351 is an apocalyptic number.

21047351 is a deficient number, since it is larger than the sum of its proper divisors (1854073).

21047351 is a wasteful number, since it uses less digits than its factorization.

21047351 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16801.

The product of its (nonzero) digits is 840, while the sum is 23.

The square root of 21047351 is about 4587.7392035729. The cubic root of 21047351 is about 276.0996235963.

The spelling of 21047351 in words is "twenty-one million, forty-seven thousand, three hundred fifty-one".