642401561 has 8 divisors (see below), whose sum is σ = 673023744. Its totient is φ = 612398160.

The previous prime is 642401537. The next prime is 642401587. The reversal of 642401561 is 165104246.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-642401561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (642451561) 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, 152570 + ... + 156723.

It is an arithmetic number, because the mean of its divisors is an integer number (84127968).

Almost surely, 2^642401561 is an apocalyptic number.

It is an amenable number.

642401561 is a deficient number, since it is larger than the sum of its proper divisors (30622183).

642401561 is a wasteful number, since it uses less digits than its factorization.

642401561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 309391.

The product of its (nonzero) digits is 5760, while the sum is 29.

The square root of 642401561 is about 25345.6418541729. The cubic root of 642401561 is about 862.8504485278.

The spelling of 642401561 in words is "six hundred forty-two million, four hundred one thousand, five hundred sixty-one".