21891283451 has 2 divisors, whose sum is σ = 21891283452. Its totient is φ = 21891283450.

The previous prime is 21891283369. The next prime is 21891283489. The reversal of 21891283451 is 15438219812.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21891283451 is a prime.

It is a super-2 number, since 2×21891283451² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21891283151) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10945641725 + 10945641726.

It is an arithmetic number, because the mean of its divisors is an integer number (10945641726).

Almost surely, 2^21891283451 is an apocalyptic number.

21891283451 is a deficient number, since it is larger than the sum of its proper divisors (1).

21891283451 is an equidigital number, since it uses as much as digits as its factorization.

21891283451 is an evil number, because the sum of its binary digits is even.

The product of its digits is 138240, while the sum is 44.

The spelling of 21891283451 in words is "twenty-one billion, eight hundred ninety-one million, two hundred eighty-three thousand, four hundred fifty-one".