72121213 has 4 divisors (see below), whose sum is σ = 72293760. Its totient is φ = 71948668.

The previous prime is 72121201. The next prime is 72121223. The reversal of 72121213 is 31212127.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 72121213 - 2¹⁷ = 71990141 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 (72121223) 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, 85645 + ... + 86482.

It is an arithmetic number, because the mean of its divisors is an integer number (18073440).

Almost surely, 2^72121213 is an apocalyptic number.

It is an amenable number.

72121213 is a deficient number, since it is larger than the sum of its proper divisors (172547).

72121213 is a wasteful number, since it uses less digits than its factorization.

72121213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 172546.

The product of its digits is 168, while the sum is 19.

The square root of 72121213 is about 8492.4209151455. The cubic root of 72121213 is about 416.2500903907.

The spelling of 72121213 in words is "seventy-two million, one hundred twenty-one thousand, two hundred thirteen".