21151047 has 8 divisors (see below), whose sum is σ = 29685760. Its totient is φ = 13358520.

The previous prime is 21151027. The next prime is 21151049. The reversal of 21151047 is 74015112.

It is a happy number.

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

It is not a de Polignac number, because 21151047 - 2¹⁶ = 21085511 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21151049) 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, 185479 + ... + 185592.

It is an arithmetic number, because the mean of its divisors is an integer number (3710720).

Almost surely, 2^21151047 is an apocalyptic number.

21151047 is a deficient number, since it is larger than the sum of its proper divisors (8534713).

21151047 is a wasteful number, since it uses less digits than its factorization.

21151047 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 371093.

The product of its (nonzero) digits is 280, while the sum is 21.

The square root of 21151047 is about 4599.0267448668. The cubic root of 21151047 is about 276.5523097972.

Adding to 21151047 its reverse (74015112), we get a palindrome (95166159).

The spelling of 21151047 in words is "twenty-one million, one hundred fifty-one thousand, forty-seven".