20949887 has 4 divisors (see below), whose sum is σ = 23942736. Its totient is φ = 17957040.

The previous prime is 20949883. The next prime is 20949917. The reversal of 20949887 is 78894902.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78894902 = 2 ⋅39447451.

It is a cyclic number.

It is not a de Polignac number, because 20949887 - 2² = 20949883 is a prime.

It is a Duffinian number.

It is a plaindrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20949883) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1496414 + ... + 1496427.

It is an arithmetic number, because the mean of its divisors is an integer number (5985684).

Almost surely, 2^20949887 is an apocalyptic number.

20949887 is a deficient number, since it is larger than the sum of its proper divisors (2992849).

20949887 is an equidigital number, since it uses as much as digits as its factorization.

20949887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2992848.

The product of its (nonzero) digits is 290304, while the sum is 47.

The square root of 20949887 is about 4577.1046525069. The cubic root of 20949887 is about 275.6727857495.

The spelling of 20949887 in words is "twenty million, nine hundred forty-nine thousand, eight hundred eighty-seven".