7208121921 has 96 divisors (see below), whose sum is σ = 13218710400. Its totient is φ = 3454738560.

The previous prime is 7208121911. The next prime is 7208121923. The reversal of 7208121921 is 1291218027.

It is not a de Polignac number, because 7208121921 - 2²¹ = 7206024769 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (7208121923) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 3551535 + ... + 3553563.

It is an arithmetic number, because the mean of its divisors is an integer number (137694900).

Almost surely, 2^7208121921 is an apocalyptic number.

It is an amenable number.

7208121921 is a deficient number, since it is larger than the sum of its proper divisors (6010588479).

7208121921 is a wasteful number, since it uses less digits than its factorization.

7208121921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2096 (or 2063 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 33.

The square root of 7208121921 is about 84900.6591317170. The cubic root of 7208121921 is about 1931.7045730803.

Adding to 7208121921 its reverse (1291218027), we get a palindrome (8499339948).

The spelling of 7208121921 in words is "seven billion, two hundred eight million, one hundred twenty-one thousand, nine hundred twenty-one".