1392991021 has 8 divisors (see below), whose sum is σ = 1455398784. Its totient is φ = 1330736880.

The previous prime is 1392991007. The next prime is 1392991027. The reversal of 1392991021 is 1201992931.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1392991021 - 2⁹ = 1392990509 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1392991027) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19665 + ... + 56326.

It is an arithmetic number, because the mean of its divisors is an integer number (181924848).

Almost surely, 2^1392991021 is an apocalyptic number.

It is an amenable number.

1392991021 is a deficient number, since it is larger than the sum of its proper divisors (62407763).

1392991021 is an equidigital number, since it uses as much as digits as its factorization.

1392991021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76811.

The product of its (nonzero) digits is 8748, while the sum is 37.

The square root of 1392991021 is about 37322.7949248177. The cubic root of 1392991021 is about 1116.8189447736.

The spelling of 1392991021 in words is "one billion, three hundred ninety-two million, nine hundred ninety-one thousand, twenty-one".