21245023436 has 24 divisors (see below), whose sum is σ = 45758512800. Its totient is φ = 8404624512.

The previous prime is 21245023427. The next prime is 21245023469. The reversal of 21245023436 is 63432054212.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29182361 + ... + 29183088.

It is an arithmetic number, because the mean of its divisors is an integer number (1906604700).

Almost surely, 2^21245023436 is an apocalyptic number.

21245023436 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21245023436 is an abundant number, since it is smaller than the sum of its proper divisors (24513489364).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21245023436 is a wasteful number, since it uses less digits than its factorization.

21245023436 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58365473 (or 58365471 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 32.

Adding to 21245023436 its reverse (63432054212), we get a palindrome (84677077648).

The spelling of 21245023436 in words is "twenty-one billion, two hundred forty-five million, twenty-three thousand, four hundred thirty-six".