21405332151 has 24 divisors (see below), whose sum is σ = 37195566720. Its totient is φ = 11587848336.

The previous prime is 21405332141. The next prime is 21405332159. The reversal of 21405332151 is 15123350412.

21405332151 is a `hidden beast` number, since 21 + 40 + 533 + 21 + 51 = 666.

It is not a de Polignac number, because 21405332151 - 2²³ = 21396943543 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21405332159) 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, 8940045 + ... + 8942438.

It is an arithmetic number, because the mean of its divisors is an integer number (1549815280).

Almost surely, 2^21405332151 is an apocalyptic number.

21405332151 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21405332151 is a deficient number, since it is larger than the sum of its proper divisors (15790234569).

21405332151 is a wasteful number, since it uses less digits than its factorization.

21405332151 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17882515 (or 17882512 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

Adding to 21405332151 its reverse (15123350412), we get a palindrome (36528682563).

The spelling of 21405332151 in words is "twenty-one billion, four hundred five million, three hundred thirty-two thousand, one hundred fifty-one".