99997972 has 6 divisors (see below), whose sum is σ = 174996458. Its totient is φ = 49998984.

The previous prime is 99997957. The next prime is 99997973. The reversal of 99997972 is 27979999.

It can be written as a sum of positive squares in only one way, i.e., 86936976 + 13060996 = 9324^2 + 3614^2 .

It is a super-2 number, since 2×99997972² = 19999188808225568, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 99997972.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99997973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12499743 + ... + 12499750.

Almost surely, 2^99997972 is an apocalyptic number.

It is an amenable number.

99997972 is a deficient number, since it is larger than the sum of its proper divisors (74998486).

99997972 is a wasteful number, since it uses less digits than its factorization.

99997972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24999497 (or 24999495 counting only the distinct ones).

The product of its digits is 5786802, while the sum is 61.

The square root of 99997972 is about 9999.8985994859. The cubic root of 99997972 is about 464.1557456260.

It can be divided in two parts, 9999 and 7972, that added together give a palindrome (17971).

The spelling of 99997972 in words is "ninety-nine million, nine hundred ninety-seven thousand, nine hundred seventy-two".