20958987 has 16 divisors (see below), whose sum is σ = 32389632. Its totient is φ = 11807040.

The previous prime is 20958979. The next prime is 20958989. The reversal of 20958987 is 78985902.

It is a happy number.

It is not a de Polignac number, because 20958987 - 2³ = 20958979 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20958989) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5538 + ... + 8519.

It is an arithmetic number, because the mean of its divisors is an integer number (2024352).

Almost surely, 2^20958987 is an apocalyptic number.

20958987 is a deficient number, since it is larger than the sum of its proper divisors (11430645).

20958987 is a wasteful number, since it uses less digits than its factorization.

20958987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14138.

The product of its (nonzero) digits is 362880, while the sum is 48.

The square root of 20958987 is about 4578.0986227909. The cubic root of 20958987 is about 275.7126946237.

It can be divided in two parts, 20958 and 987, that added together give a triangular number (21945 = T₂₀₉).

The spelling of 20958987 in words is "twenty million, nine hundred fifty-eight thousand, nine hundred eighty-seven".