21244238778 has 32 divisors (see below), whose sum is σ = 48564942336. Its totient is φ = 6068947248.

The previous prime is 21244238767. The next prime is 21244238779. The reversal of 21244238778 is 87783244212.

It is a happy number.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (21244238779) 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, 315525 + ... + 376887.

It is an arithmetic number, because the mean of its divisors is an integer number (1517654448).

Almost surely, 2^21244238778 is an apocalyptic number.

21244238778 is an abundant number, since it is smaller than the sum of its proper divisors (27320703558).

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

21244238778 is a wasteful number, since it uses less digits than its factorization.

21244238778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69618.

The product of its digits is 1204224, while the sum is 48.

The spelling of 21244238778 in words is "twenty-one billion, two hundred forty-four million, two hundred thirty-eight thousand, seven hundred seventy-eight".