7215101721 has 24 divisors (see below), whose sum is σ = 10579907520. Its totient is φ = 4737247200.

The previous prime is 7215101687. The next prime is 7215101779. The reversal of 7215101721 is 1271015127.

It is not a de Polignac number, because 7215101721 - 2²⁷ = 7080883993 is a prime.

It is not an unprimeable number, because it can be changed into a prime (7215101221) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 646890 + ... + 657948.

It is an arithmetic number, because the mean of its divisors is an integer number (440829480).

Almost surely, 2^7215101721 is an apocalyptic number.

7215101721 is a gapful number since it is divisible by the number (71) formed by its first and last digit.

It is an amenable number.

7215101721 is a deficient number, since it is larger than the sum of its proper divisors (3364805799).

7215101721 is a wasteful number, since it uses less digits than its factorization.

7215101721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12157 (or 12154 counting only the distinct ones).

The product of its (nonzero) digits is 980, while the sum is 27.

The square root of 7215101721 is about 84941.7548735603. The cubic root of 7215101721 is about 1932.3278774640.

Adding to 7215101721 its reverse (1271015127), we get a palindrome (8486116848).

The spelling of 7215101721 in words is "seven billion, two hundred fifteen million, one hundred one thousand, seven hundred twenty-one".