21949547 has 4 divisors (see below), whose sum is σ = 22542816. Its totient is φ = 21356280.

The previous prime is 21949531. The next prime is 21949553. The reversal of 21949547 is 74594912.

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 21949547 - 2⁴ = 21949531 is a prime.

It is a super-2 number, since 2×21949547² = 963565227010418, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21949507) 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, 296579 + ... + 296652.

It is an arithmetic number, because the mean of its divisors is an integer number (5635704).

Almost surely, 2^21949547 is an apocalyptic number.

21949547 is a deficient number, since it is larger than the sum of its proper divisors (593269).

21949547 is an equidigital number, since it uses as much as digits as its factorization.

21949547 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 593268.

The product of its digits is 90720, while the sum is 41.

The square root of 21949547 is about 4685.0343648686. The cubic root of 21949547 is about 279.9895701897.

The spelling of 21949547 in words is "twenty-one million, nine hundred forty-nine thousand, five hundred forty-seven".