21007326544 has 10 divisors (see below), whose sum is σ = 40701695210. Its totient is φ = 10503663264.

The previous prime is 21007326521. The next prime is 21007326577. The reversal of 21007326544 is 44562370012.

It can be written as a sum of positive squares in only one way, i.e., 18555888400 + 2451438144 = 136220^2 + 49512^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 656478939 + ... + 656478970.

It is an arithmetic number, because the mean of its divisors is an integer number (4070169521).

Almost surely, 2^21007326544 is an apocalyptic number.

It is an amenable number.

21007326544 is a deficient number, since it is larger than the sum of its proper divisors (19694368666).

21007326544 is a wasteful number, since it uses less digits than its factorization.

21007326544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1312957917 (or 1312957911 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 34.

Adding to 21007326544 its reverse (44562370012), we get a palindrome (65569696556).

The spelling of 21007326544 in words is "twenty-one billion, seven million, three hundred twenty-six thousand, five hundred forty-four".