61821870 has 32 divisors (see below), whose sum is σ = 161861760. Its totient is φ = 14987040.

The previous prime is 61821841. The next prime is 61821871. The reversal of 61821870 is 7812816.

It is a happy number.

It is a super-2 number, since 2×61821870² = 7643887220593800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61821871) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 93340 + ... + 93999.

It is an arithmetic number, because the mean of its divisors is an integer number (5058180).

Almost surely, 2^61821870 is an apocalyptic number.

61821870 is an abundant number, since it is smaller than the sum of its proper divisors (100039890).

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

61821870 is a wasteful number, since it uses less digits than its factorization.

61821870 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 187360.

The product of its (nonzero) digits is 5376, while the sum is 33.

The square root of 61821870 is about 7862.6884715090. The cubic root of 61821870 is about 395.4097547848.

The spelling of 61821870 in words is "sixty-one million, eight hundred twenty-one thousand, eight hundred seventy".