213121645801 has 9 divisors (see below), whose sum is σ = 220737948951. Its totient is φ = 205759697304.

The previous prime is 213121645777. The next prime is 213121645811. The reversal of 213121645801 is 108546121312.

The square root of 213121645801 is 461651.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 111755821401 + 101365824400 = 334299^2 + 318380^2 .

It is not a de Polignac number, because 213121645801 - 2¹¹ = 213121643753 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (213121645811) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 13379920 + ... + 13395838.

Almost surely, 2^213121645801 is an apocalyptic number.

213121645801 is the 461651-st square number.

213121645801 is the 230826-th centered octagonal number.

It is an amenable number.

213121645801 is a deficient number, since it is larger than the sum of its proper divisors (7616303150).

213121645801 is an frugal number, since it uses more digits than its factorization.

213121645801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31896 (or 15948 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 34.

The spelling of 213121645801 in words is "two hundred thirteen billion, one hundred twenty-one million, six hundred forty-five thousand, eight hundred one".