20402087 has 2 divisors, whose sum is σ = 20402088. Its totient is φ = 20402086.

The previous prime is 20402021. The next prime is 20402099. The reversal of 20402087 is 78020402.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20402087 - 2⁸ = 20401831 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20402017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10201043 + 10201044.

It is an arithmetic number, because the mean of its divisors is an integer number (10201044).

Almost surely, 2^20402087 is an apocalyptic number.

20402087 is a deficient number, since it is larger than the sum of its proper divisors (1).

20402087 is an equidigital number, since it uses as much as digits as its factorization.

20402087 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 896, while the sum is 23.

The square root of 20402087 is about 4516.8669451291. The cubic root of 20402087 is about 273.2487591138.

Adding to 20402087 its reverse (78020402), we get a palindrome (98422489).

The spelling of 20402087 in words is "twenty million, four hundred two thousand, eighty-seven".