3921742656 has 140 divisors (see below), whose sum is σ = 12519740772. Its totient is φ = 1206669312.

The previous prime is 3921742639. The next prime is 3921742667. The reversal of 3921742656 is 6562471293.

3921742656 is a `hidden beast` number, since 3 + 9 + 217 + 426 + 5 + 6 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1219406400 + 2702336256 = 34920^2 + 51984^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 38296 + ... + 96488.

Almost surely, 2^3921742656 is an apocalyptic number.

3921742656 is a gapful number since it is divisible by the number (36) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 3921742656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (6259870386).

3921742656 is an abundant number, since it is smaller than the sum of its proper divisors (8597998116).

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

3921742656 is a wasteful number, since it uses less digits than its factorization.

3921742656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58230 (or 58211 counting only the distinct ones).

The product of its digits is 544320, while the sum is 45.

The square root of 3921742656 is about 62623.8185996351. The cubic root of 3921742656 is about 1576.9806483188.

It can be divided in two parts, 3921742 and 656, that multiplied together give a palindrome (2572662752).

The spelling of 3921742656 in words is "three billion, nine hundred twenty-one million, seven hundred forty-two thousand, six hundred fifty-six".