21367951 has 12 divisors (see below), whose sum is σ = 24606504. Its totient is φ = 18399600.

The previous prime is 21367933. The next prime is 21367979. The reversal of 21367951 is 15976312.

It is not a de Polignac number, because 21367951 - 2⁵ = 21367919 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 (21367901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1281 + ... + 6661.

It is an arithmetic number, because the mean of its divisors is an integer number (2050542).

Almost surely, 2^21367951 is an apocalyptic number.

21367951 is a deficient number, since it is larger than the sum of its proper divisors (3238553).

21367951 is a wasteful number, since it uses less digits than its factorization.

21367951 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5430 (or 5411 counting only the distinct ones).

The product of its digits is 11340, while the sum is 34.

The square root of 21367951 is about 4622.5481068346. The cubic root of 21367951 is about 277.4944446038.

The spelling of 21367951 in words is "twenty-one million, three hundred sixty-seven thousand, nine hundred fifty-one".