72121211 has 4 divisors (see below), whose sum is σ = 72353424. Its totient is φ = 71889000.

The previous prime is 72121201. The next prime is 72121223. The reversal of 72121211 is 11212127.

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

It is a cyclic number.

It is not a de Polignac number, because 72121211 - 2¹⁴ = 72104827 is a prime.

It is a super-2 number, since 2×72121211² = 10402938152213042, which contains 22 as substring.

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 72121211.

It is not an unprimeable number, because it can be changed into a prime (72121201) 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, 115640 + ... + 116261.

It is an arithmetic number, because the mean of its divisors is an integer number (18088356).

Almost surely, 2^72121211 is an apocalyptic number.

72121211 is a deficient number, since it is larger than the sum of its proper divisors (232213).

72121211 is a wasteful number, since it uses less digits than its factorization.

72121211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 232212.

The product of its digits is 56, while the sum is 17.

The square root of 72121211 is about 8492.4207973934. The cubic root of 72121211 is about 416.2500865430.

Adding to 72121211 its reverse (11212127), we get a palindrome (83333338).

The spelling of 72121211 in words is "seventy-two million, one hundred twenty-one thousand, two hundred eleven".