21492047 has 4 divisors (see below), whose sum is σ = 21508536. Its totient is φ = 21475560.

The previous prime is 21492043. The next prime is 21492061. The reversal of 21492047 is 74029412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21492047 - 2² = 21492043 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 (21492043) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6104 + ... + 8957.

It is an arithmetic number, because the mean of its divisors is an integer number (5377134).

Almost surely, 2^21492047 is an apocalyptic number.

21492047 is a deficient number, since it is larger than the sum of its proper divisors (16489).

21492047 is a wasteful number, since it uses less digits than its factorization.

21492047 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16488.

The product of its (nonzero) digits is 4032, while the sum is 29.

The square root of 21492047 is about 4635.9515743804. The cubic root of 21492047 is about 278.0305980503.

The spelling of 21492047 in words is "twenty-one million, four hundred ninety-two thousand, forty-seven".