642452981 has 8 divisors (see below), whose sum is σ = 659904960. Its totient is φ = 625115232.

The previous prime is 642452971. The next prime is 642452989. The reversal of 642452981 is 189254246.

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

It is a de Polignac number, because none of the positive numbers 2^k-642452981 is a prime.

It is a super-2 number, since 2×642452981² = 825491665591572722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642452989) 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, 17096 + ... + 39713.

It is an arithmetic number, because the mean of its divisors is an integer number (82488120).

Almost surely, 2^642452981 is an apocalyptic number.

It is an amenable number.

642452981 is a deficient number, since it is larger than the sum of its proper divisors (17451979).

642452981 is a wasteful number, since it uses less digits than its factorization.

642452981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57115.

The product of its digits is 138240, while the sum is 41.

The square root of 642452981 is about 25346.6562094490. The cubic root of 642452981 is about 862.8734697391.

The spelling of 642452981 in words is "six hundred forty-two million, four hundred fifty-two thousand, nine hundred eighty-one".