21405274007 has 4 divisors (see below), whose sum is σ = 23051833560. Its totient is φ = 19758714456.

The previous prime is 21405273997. The next prime is 21405274031. The reversal of 21405274007 is 70047250412.

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

It is not a de Polignac number, because 21405274007 - 2⁶ = 21405273943 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21405274067) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 823279757 + ... + 823279782.

It is an arithmetic number, because the mean of its divisors is an integer number (5762958390).

Almost surely, 2^21405274007 is an apocalyptic number.

21405274007 is a deficient number, since it is larger than the sum of its proper divisors (1646559553).

21405274007 is a wasteful number, since it uses less digits than its factorization.

21405274007 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1646559552.

The product of its (nonzero) digits is 15680, while the sum is 32.

The spelling of 21405274007 in words is "twenty-one billion, four hundred five million, two hundred seventy-four thousand, seven".