21366451001643 has 24 divisors (see below), whose sum is σ = 31451864063424. Its totient is φ = 12892318536240.

The previous prime is 21366451001633. The next prime is 21366451001741. The reversal of 21366451001643 is 34610015466312.

It is a happy number.

It is not a de Polignac number, because 21366451001643 - 2¹³ = 21366450993451 is a prime.

It is a super-2 number, since 2×21366451001643² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21366451001595 and 21366451001604.

It is not an unprimeable number, because it can be changed into a prime (21366451001633) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 129566821 + ... + 129731622.

It is an arithmetic number, because the mean of its divisors is an integer number (1310494335976).

Almost surely, 2^{21366451001643} is an apocalyptic number.

21366451001643 is a deficient number, since it is larger than the sum of its proper divisors (10085413061781).

21366451001643 is a wasteful number, since it uses less digits than its factorization.

21366451001643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 259298695 (or 259298684 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 42.

Adding to 21366451001643 its reverse (34610015466312), we get a palindrome (55976466467955).

The spelling of 21366451001643 in words is "twenty-one trillion, three hundred sixty-six billion, four hundred fifty-one million, one thousand, six hundred forty-three".