61851690 has 36 divisors (see below), whose sum is σ = 161008614. Its totient is φ = 16473888.

The previous prime is 61851649. The next prime is 61851703. The reversal of 61851690 is 9615816.

It can be written as a sum of positive squares in 3 ways, for example, as 53012961 + 8838729 = 7281^2 + 2973^2 .

It is a super-2 number, since 2×61851690² = 7651263111712200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 74196 + ... + 75024.

Almost surely, 2^61851690 is an apocalyptic number.

61851690 is an abundant number, since it is smaller than the sum of its proper divisors (99156924).

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

61851690 is an equidigital number, since it uses as much as digits as its factorization.

61851690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1671 (or 839 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 61851690 is about 7864.5845408388. The cubic root of 61851690 is about 395.4733203352.

Multiplying 61851690 by its product of nonzero digits (12960), we get a square (801597902400 = 895320²).

It can be divided in two parts, 6185 and 1690, that added together give a triangular number (7875 = T₁₂₅).

The spelling of 61851690 in words is "sixty-one million, eight hundred fifty-one thousand, six hundred ninety".