172642640 has 20 divisors (see below), whose sum is σ = 401394324. Its totient is φ = 69057024.

The previous prime is 172642619. The next prime is 172642661. The reversal of 172642640 is 46246271.

172642640 = 344² + 345² + ... + 823².

It is an interprime number because it is at equal distance from previous prime (172642619) and next prime (172642661).

It can be written as a sum of positive squares in 2 ways, for example, as 115004176 + 57638464 = 10724^2 + 7592^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-2 number, since 2×172642640² = 59610962292339200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 172642597 and 172642606.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1078937 + ... + 1079096.

Almost surely, 2^172642640 is an apocalyptic number.

172642640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

172642640 is an abundant number, since it is smaller than the sum of its proper divisors (228751684).

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

172642640 is a wasteful number, since it uses less digits than its factorization.

172642640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2158046 (or 2158040 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 32.

The square root of 172642640 is about 13139.3546264647. The cubic root of 172642640 is about 556.8215345142.

The spelling of 172642640 in words is "one hundred seventy-two million, six hundred forty-two thousand, six hundred forty".