3642681981 has 4 divisors (see below), whose sum is σ = 4856909312. Its totient is φ = 2428454652.

The previous prime is 3642681949. The next prime is 3642682003. The reversal of 3642681981 is 1891862463.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1891862463 = 3 ⋅630620821.

It is not a de Polignac number, because 3642681981 - 2⁵ = 3642681949 is a prime.

It is a super-2 number, since 2×3642681981² = 26538264029404168722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 3642681981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3642681901) 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, 607113661 + ... + 607113666.

It is an arithmetic number, because the mean of its divisors is an integer number (1214227328).

Almost surely, 2^3642681981 is an apocalyptic number.

It is an amenable number.

3642681981 is a deficient number, since it is larger than the sum of its proper divisors (1214227331).

3642681981 is a wasteful number, since it uses less digits than its factorization.

3642681981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1214227330.

The product of its digits is 497664, while the sum is 48.

The square root of 3642681981 is about 60354.6351244045. The cubic root of 3642681981 is about 1538.6520477066.

The spelling of 3642681981 in words is "three billion, six hundred forty-two million, six hundred eighty-one thousand, nine hundred eighty-one".