20400249659 has 4 divisors (see below), whose sum is σ = 20403300720. Its totient is φ = 20397198600.

The previous prime is 20400249629. The next prime is 20400249677. The reversal of 20400249659 is 95694200402.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 20400249659 - 2¹² = 20400245563 is a prime.

It is a super-2 number, since 2×20400249659² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20400249629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1515479 + ... + 1528880.

It is an arithmetic number, because the mean of its divisors is an integer number (5100825180).

Almost surely, 2^20400249659 is an apocalyptic number.

20400249659 is a deficient number, since it is larger than the sum of its proper divisors (3051061).

20400249659 is an equidigital number, since it uses as much as digits as its factorization.

20400249659 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3051060.

The product of its (nonzero) digits is 155520, while the sum is 41.

The spelling of 20400249659 in words is "twenty billion, four hundred million, two hundred forty-nine thousand, six hundred fifty-nine".