642145731 has 16 divisors (see below), whose sum is σ = 881562528. Its totient is φ = 415520000.

The previous prime is 642145729. The next prime is 642145739. The reversal of 642145731 is 137541246.

642145731 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 642145731 - 2¹ = 642145729 is a prime.

It is a super-2 number, since 2×642145731² = 824702279683048722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 642145692 and 642145701.

It is not an unprimeable number, because it can be changed into a prime (642145739) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10981 + ... + 37481.

It is an arithmetic number, because the mean of its divisors is an integer number (55097658).

Almost surely, 2^642145731 is an apocalyptic number.

642145731 is a deficient number, since it is larger than the sum of its proper divisors (239416797).

642145731 is a wasteful number, since it uses less digits than its factorization.

642145731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26742.

The product of its digits is 20160, while the sum is 33.

The square root of 642145731 is about 25340.5945273587. The cubic root of 642145731 is about 862.7358927976.

Adding to 642145731 its reverse (137541246), we get a palindrome (779686977).

The spelling of 642145731 in words is "six hundred forty-two million, one hundred forty-five thousand, seven hundred thirty-one".