213521807851 has 4 divisors (see below), whose sum is σ = 232932881304. Its totient is φ = 194110734400.

The previous prime is 213521807839. The next prime is 213521807857. The reversal of 213521807851 is 158708125312.

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

It is not a de Polignac number, because 213521807851 - 2⁹ = 213521807339 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 213521807798 and 213521807807.

It is not an unprimeable number, because it can be changed into a prime (213521807857) 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, 9705536710 + ... + 9705536731.

It is an arithmetic number, because the mean of its divisors is an integer number (58233220326).

Almost surely, 2^213521807851 is an apocalyptic number.

213521807851 is a deficient number, since it is larger than the sum of its proper divisors (19411073453).

213521807851 is a wasteful number, since it uses less digits than its factorization.

213521807851 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19411073452.

The product of its (nonzero) digits is 134400, while the sum is 43.

The spelling of 213521807851 in words is "two hundred thirteen billion, five hundred twenty-one million, eight hundred seven thousand, eight hundred fifty-one".