20422987 has 4 divisors (see below), whose sum is σ = 21994000. Its totient is φ = 18851976.

The previous prime is 20422951. The next prime is 20422993. The reversal of 20422987 is 78922402.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 20422987 - 2⁷ = 20422859 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20425987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 785487 + ... + 785512.

It is an arithmetic number, because the mean of its divisors is an integer number (5498500).

Almost surely, 2^20422987 is an apocalyptic number.

20422987 is a deficient number, since it is larger than the sum of its proper divisors (1571013).

20422987 is a wasteful number, since it uses less digits than its factorization.

20422987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1571012.

The product of its (nonzero) digits is 16128, while the sum is 34.

The square root of 20422987 is about 4519.1799034781. The cubic root of 20422987 is about 273.3420330697.

The spelling of 20422987 in words is "twenty million, four hundred twenty-two thousand, nine hundred eighty-seven".