213607249821 has 30 divisors (see below), whose sum is σ = 371189022270. Its totient is φ = 122061283344.

The previous prime is 213607249819. The next prime is 213607249837. The reversal of 213607249821 is 128942706312.

213607249821 is a `hidden beast` number, since 2 + 13 + 60 + 72 + 498 + 21 = 666.

It can be written as a sum of positive squares in only one way, i.e., 204497501796 + 9109748025 = 452214^2 + 95445^2 .

It is not a de Polignac number, because 213607249821 - 2¹ = 213607249819 is a prime.

It is a super-2 number, since 2×213607249821² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213607249421) by changing a digit.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 26905486 + ... + 26913423.

It is an arithmetic number, because the mean of its divisors is an integer number (12372967409).

Almost surely, 2^213607249821 is an apocalyptic number.

213607249821 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

213607249821 is a deficient number, since it is larger than the sum of its proper divisors (157581772449).

213607249821 is an equidigital number, since it uses as much as digits as its factorization.

213607249821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53818935 (or 53818919 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 45.

The spelling of 213607249821 in words is "two hundred thirteen billion, six hundred seven million, two hundred forty-nine thousand, eight hundred twenty-one".