21770779968 has 336 divisors, whose sum is σ = 74850101760. Its totient is φ = 6186958848.

The previous prime is 21770779967. The next prime is 21770779969. The reversal of 21770779968 is 86997707712.

It is an interprime number because it is at equal distance from previous prime (21770779967) and next prime (21770779969).

It is a tau number, because it is divible by the number of its divisors (336).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21770779967) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 18881280 + ... + 18882432.

It is an arithmetic number, because the mean of its divisors is an integer number (222768160).

Almost surely, 2^21770779968 is an apocalyptic number.

21770779968 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21770779968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37425050880).

21770779968 is an abundant number, since it is smaller than the sum of its proper divisors (53079321792).

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

21770779968 is a wasteful number, since it uses less digits than its factorization.

21770779968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1411 (or 1388 counting only the distinct ones).

The product of its (nonzero) digits is 18670176, while the sum is 63.

The spelling of 21770779968 in words is "twenty-one billion, seven hundred seventy million, seven hundred seventy-nine thousand, nine hundred sixty-eight".