20919047 has 4 divisors (see below), whose sum is σ = 21313800. Its totient is φ = 20524296.

The previous prime is 20919037. The next prime is 20919049. The reversal of 20919047 is 74091902.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 74091902 = 2 ⋅37045951.

It is a cyclic number.

It is not a de Polignac number, because 20919047 - 2¹² = 20914951 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 (20919049) 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, 197297 + ... + 197402.

It is an arithmetic number, because the mean of its divisors is an integer number (5328450).

Almost surely, 2^20919047 is an apocalyptic number.

20919047 is a deficient number, since it is larger than the sum of its proper divisors (394753).

20919047 is an equidigital number, since it uses as much as digits as its factorization.

20919047 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 394752.

The product of its (nonzero) digits is 4536, while the sum is 32.

The square root of 20919047 is about 4573.7344697741. The cubic root of 20919047 is about 275.5374481239.

The spelling of 20919047 in words is "twenty million, nine hundred nineteen thousand, forty-seven".