21361742656 has 28 divisors (see below), whose sum is σ = 42397931968. Its totient is φ = 10678799232.

The previous prime is 21361742653. The next prime is 21361742657. The reversal of 21361742656 is 65624716312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21361742653) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 331855 + ... + 390961.

It is an arithmetic number, because the mean of its divisors is an integer number (1514211856).

Almost surely, 2^21361742656 is an apocalyptic number.

It is an amenable number.

21361742656 is a deficient number, since it is larger than the sum of its proper divisors (21036189312).

21361742656 is an equidigital number, since it uses as much as digits as its factorization.

21361742656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64766 (or 64756 counting only the distinct ones).

The product of its digits is 362880, while the sum is 43.

The spelling of 21361742656 in words is "twenty-one billion, three hundred sixty-one million, seven hundred forty-two thousand, six hundred fifty-six".