21772245640 has 32 divisors (see below), whose sum is σ = 49121066880. Its totient is φ = 8685162432.

The previous prime is 21772245623. The next prime is 21772245641. The reversal of 21772245640 is 4654227712.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 21772245593 and 21772245602.

It is not an unprimeable number, because it can be changed into a prime (21772245641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 726882 + ... + 756241.

It is an arithmetic number, because the mean of its divisors is an integer number (1535033340).

Almost surely, 2^21772245640 is an apocalyptic number.

21772245640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21772245640 is an abundant number, since it is smaller than the sum of its proper divisors (27348821240).

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

21772245640 is a wasteful number, since it uses less digits than its factorization.

21772245640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1483501 (or 1483497 counting only the distinct ones).

The product of its (nonzero) digits is 188160, while the sum is 40.

It can be divided in two parts, 217722 and 45640, that added together give a palindrome (263362).

The spelling of 21772245640 in words is "twenty-one billion, seven hundred seventy-two million, two hundred forty-five thousand, six hundred forty".