1861657420 has 48 divisors (see below), whose sum is σ = 4730806080. Its totient is φ = 600735744.

The previous prime is 1861657409. The next prime is 1861657423. The reversal of 1861657420 is 247561681.

It is not an unprimeable number, because it can be changed into a prime (1861657423) 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, 388725 + ... + 393484.

It is an arithmetic number, because the mean of its divisors is an integer number (98558460).

Almost surely, 2^1861657420 is an apocalyptic number.

1861657420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1861657420 is an abundant number, since it is smaller than the sum of its proper divisors (2869148660).

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

1861657420 is a wasteful number, since it uses less digits than its factorization.

1861657420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 782242 (or 782240 counting only the distinct ones).

The product of its (nonzero) digits is 80640, while the sum is 40.

The square root of 1861657420 is about 43146.9282800062. The cubic root of 1861657420 is about 1230.1741265371.

The spelling of 1861657420 in words is "one billion, eight hundred sixty-one million, six hundred fifty-seven thousand, four hundred twenty".