20987293 has 4 divisors (see below), whose sum is σ = 21899808. Its totient is φ = 20074780.

The previous prime is 20987287. The next prime is 20987321. The reversal of 20987293 is 39278902.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20987293 - 2⁵ = 20987261 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 (20987243) 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, 456223 + ... + 456268.

It is an arithmetic number, because the mean of its divisors is an integer number (5474952).

Almost surely, 2^20987293 is an apocalyptic number.

20987293 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

20987293 is a deficient number, since it is larger than the sum of its proper divisors (912515).

20987293 is an equidigital number, since it uses as much as digits as its factorization.

20987293 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 912514.

The product of its (nonzero) digits is 54432, while the sum is 40.

The square root of 20987293 is about 4581.1890377936. The cubic root of 20987293 is about 275.8367593477.

The spelling of 20987293 in words is "twenty million, nine hundred eighty-seven thousand, two hundred ninety-three".