1642257881 has 4 divisors (see below), whose sum is σ = 1791554064. Its totient is φ = 1492961700.

The previous prime is 1642257857. The next prime is 1642257889. The reversal of 1642257881 is 1887522461.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1642257881 is a prime.

It is a super-2 number, since 2×1642257881² = 5394021895413220322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1642257889) 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, 74648075 + ... + 74648096.

It is an arithmetic number, because the mean of its divisors is an integer number (447888516).

Almost surely, 2^1642257881 is an apocalyptic number.

1642257881 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1642257881 is a deficient number, since it is larger than the sum of its proper divisors (149296183).

1642257881 is a wasteful number, since it uses less digits than its factorization.

1642257881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149296182.

The product of its digits is 215040, while the sum is 44.

The square root of 1642257881 is about 40524.7810728201. The cubic root of 1642257881 is about 1179.8146508168.

The spelling of 1642257881 in words is "one billion, six hundred forty-two million, two hundred fifty-seven thousand, eight hundred eighty-one".