126399981 has 16 divisors (see below), whose sum is σ = 178675200. Its totient is φ = 79208448.

The previous prime is 126399979. The next prime is 126400013. The reversal of 126399981 is 189993621.

It is not a de Polignac number, because 126399981 - 2¹ = 126399979 is a prime.

It is a super-2 number, since 2×126399981² = 31953910393600722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 126399981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (126399901) 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, 70980 + ... + 72738.

It is an arithmetic number, because the mean of its divisors is an integer number (11167200).

Almost surely, 2^126399981 is an apocalyptic number.

It is an amenable number.

126399981 is a deficient number, since it is larger than the sum of its proper divisors (52275219).

126399981 is a wasteful number, since it uses less digits than its factorization.

126399981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3188.

The product of its digits is 209952, while the sum is 48.

The square root of 126399981 is about 11242.7746130570. The cubic root of 126399981 is about 501.8597156727.

The spelling of 126399981 in words is "one hundred twenty-six million, three hundred ninety-nine thousand, nine hundred eighty-one".