66721974 has 32 divisors (see below), whose sum is σ = 154141056. Its totient is φ = 19029120.

The previous prime is 66721969. The next prime is 66721997. The reversal of 66721974 is 47912766.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28612 + ... + 30855.

It is an arithmetic number, because the mean of its divisors is an integer number (4816908).

Almost surely, 2^66721974 is an apocalyptic number.

66721974 is an abundant number, since it is smaller than the sum of its proper divisors (87419082).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66721974 is a wasteful number, since it uses less digits than its factorization.

66721974 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59500.

The product of its digits is 127008, while the sum is 42.

The square root of 66721974 is about 8168.3519757660. The cubic root of 66721974 is about 405.5922321688.

It can be divided in two parts, 6672 and 1974, that added together give a triangular number (8646 = T₁₃₁).

The spelling of 66721974 in words is "sixty-six million, seven hundred twenty-one thousand, nine hundred seventy-four".