21207235034407 has 4 divisors (see below), whose sum is σ = 21224079543240. Its totient is φ = 21190390525576.

The previous prime is 21207235034393. The next prime is 21207235034431. The reversal of 21207235034407 is 70443053270212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21207235034407 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21207235034407.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21207235004407) 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, 8422252528 + ... + 8422255045.

It is an arithmetic number, because the mean of its divisors is an integer number (5306019885810).

Almost surely, 2^{21207235034407} is an apocalyptic number.

21207235034407 is a deficient number, since it is larger than the sum of its proper divisors (16844508833).

21207235034407 is a wasteful number, since it uses less digits than its factorization.

21207235034407 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16844508832.

The product of its (nonzero) digits is 282240, while the sum is 40.

The spelling of 21207235034407 in words is "twenty-one trillion, two hundred seven billion, two hundred thirty-five million, thirty-four thousand, four hundred seven".