7155298921 has 3 divisors (see below), whose sum is σ = 7155383511. Its totient is φ = 7155214332.

The previous prime is 7155298879. The next prime is 7155298933. The reversal of 7155298921 is 1298925517.

The square root of 7155298921 is 84589.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 6062335321 + 1092963600 = 77861^2 + 33060^2 .

It is not a de Polignac number, because 7155298921 - 2¹⁹ = 7154774633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7155298951) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 42295 + ... + 126883.

It is an arithmetic number, because the mean of its divisors is an integer number (2385127837).

Almost surely, 2^7155298921 is an apocalyptic number.

7155298921 is the 84589-th square number.

7155298921 is the 42295-th centered octagonal number.

It is an amenable number.

7155298921 is a deficient number, since it is larger than the sum of its proper divisors (84590).

7155298921 is an frugal number, since it uses more digits than its factorization.

7155298921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169178 (or 84589 counting only the distinct ones).

The product of its digits is 453600, while the sum is 49.

The cubic root of 7155298921 is about 1926.9743208128.

Multiplying 7155298921 by its sum of digits (49), we get a square (350609647129 = 592123²).

The spelling of 7155298921 in words is "seven billion, one hundred fifty-five million, two hundred ninety-eight thousand, nine hundred twenty-one".