81972002 has 12 divisors (see below), whose sum is σ = 143032950. Its totient is φ = 35130816.

The previous prime is 81972001. The next prime is 81972031. The reversal of 81972002 is 20027918.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 52693081 + 29278921 = 7259^2 + 5411^2 .

It is a super-2 number, since 2×81972002² = 13438818223776008, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81972001) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 418127 + ... + 418322.

Almost surely, 2^81972002 is an apocalyptic number.

81972002 is a deficient number, since it is larger than the sum of its proper divisors (61060948).

81972002 is a wasteful number, since it uses less digits than its factorization.

81972002 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 836465 (or 836458 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 29.

The square root of 81972002 is about 9053.8390752211. The cubic root of 81972002 is about 434.3986970975.

The spelling of 81972002 in words is "eighty-one million, nine hundred seventy-two thousand, two".