3720021681 has 8 divisors (see below), whose sum is σ = 4964063104. Its totient is φ = 2477997360.

The previous prime is 3720021677. The next prime is 3720021689. The reversal of 3720021681 is 1861200273.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 3720021681 - 2² = 3720021677 is a prime.

It is a super-2 number, since 2×3720021681² = 27677122614220131522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3720021689) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 499966 + ... + 507351.

It is an arithmetic number, because the mean of its divisors is an integer number (620507888).

Almost surely, 2^3720021681 is an apocalyptic number.

It is an amenable number.

3720021681 is a deficient number, since it is larger than the sum of its proper divisors (1244041423).

3720021681 is a wasteful number, since it uses less digits than its factorization.

3720021681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1008551.

The product of its (nonzero) digits is 4032, while the sum is 30.

The square root of 3720021681 is about 60991.9804646480. The cubic root of 3720021681 is about 1549.4651891985.

The spelling of 3720021681 in words is "three billion, seven hundred twenty million, twenty-one thousand, six hundred eighty-one".