997519021 has 4 divisors (see below), whose sum is σ = 999272700. Its totient is φ = 995765344.

The previous prime is 997518967. The next prime is 997519027. The reversal of 997519021 is 120915799.

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

It can be written as a sum of positive squares in 2 ways, for example, as 384708996 + 612810025 = 19614^2 + 24755^2 .

It is a cyclic number.

It is not a de Polignac number, because 997519021 - 2¹⁷ = 997387949 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 (997519027) 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, 875986 + ... + 877123.

It is an arithmetic number, because the mean of its divisors is an integer number (249818175).

Almost surely, 2^997519021 is an apocalyptic number.

It is an amenable number.

997519021 is a deficient number, since it is larger than the sum of its proper divisors (1753679).

997519021 is a wasteful number, since it uses less digits than its factorization.

997519021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1753678.

The product of its (nonzero) digits is 51030, while the sum is 43.

The square root of 997519021 is about 31583.5245183308. The cubic root of 997519021 is about 999.1723221384.

The spelling of 997519021 in words is "nine hundred ninety-seven million, five hundred nineteen thousand, twenty-one".