61820172 has 36 divisors (see below), whose sum is σ = 162057896. Its totient is φ = 20606400.

The previous prime is 61820119. The next prime is 61820173. The reversal of 61820172 is 27102816.

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×61820172² = 7643467332219168, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (61820173) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 30829 + ... + 32772.

Almost surely, 2^61820172 is an apocalyptic number.

It is an amenable number.

61820172 is an abundant number, since it is smaller than the sum of its proper divisors (100237724).

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

61820172 is a wasteful number, since it uses less digits than its factorization.

61820172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63620 (or 63606 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 27.

The square root of 61820172 is about 7862.5804924338. The cubic root of 61820172 is about 395.4061346425.

Adding to 61820172 its reverse (27102816), we get a palindrome (88922988).

The spelling of 61820172 in words is "sixty-one million, eight hundred twenty thousand, one hundred seventy-two".