21250640318 has 4 divisors (see below), whose sum is σ = 31875960480. Its totient is φ = 10625320158.

The previous prime is 21250640317. The next prime is 21250640351. The reversal of 21250640318 is 81304605212.

It is a semiprime because it is the product of two primes.

It is a super-2 number, since 2×21250640318² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21250640317) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5312660078 + ... + 5312660081.

It is an arithmetic number, because the mean of its divisors is an integer number (7968990120).

Almost surely, 2^21250640318 is an apocalyptic number.

21250640318 is a deficient number, since it is larger than the sum of its proper divisors (10625320162).

21250640318 is a wasteful number, since it uses less digits than its factorization.

21250640318 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10625320161.

The product of its (nonzero) digits is 11520, while the sum is 32.

The spelling of 21250640318 in words is "twenty-one billion, two hundred fifty million, six hundred forty thousand, three hundred eighteen".