20469987 has 12 divisors (see below), whose sum is σ = 29802240. Its totient is φ = 13538448.

The previous prime is 20469983. The next prime is 20470001. The reversal of 20469987 is 78996402.

It is a happy number.

It is not a de Polignac number, because 20469987 - 2² = 20469983 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20469983) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7812 + ... + 10097.

It is an arithmetic number, because the mean of its divisors is an integer number (2483520).

Almost surely, 2^20469987 is an apocalyptic number.

20469987 is a deficient number, since it is larger than the sum of its proper divisors (9332253).

20469987 is a wasteful number, since it uses less digits than its factorization.

20469987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18042 (or 18039 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 45.

The square root of 20469987 is about 4524.3769736838. The cubic root of 20469987 is about 273.5515556862.

It can be divided in two parts, 2046 and 9987, that multiplied together give a palindrome (20433402).

The spelling of 20469987 in words is "twenty million, four hundred sixty-nine thousand, nine hundred eighty-seven".